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Rewrite the symbol correlation code, using a tiered list of
deterministic strategies in a loop. For duplicately named symbols, each
tier applies a filter with the goal of finding a 1:1 deterministic
correlation between the original and patched version of the symbol.
The three matching strategies are:
find_twin(): A funnel of progressively tighter filters. Candidates
with the same demangled name are counted at four levels: name, scope
(local-vs-global), file (strict file association), and checksum
(unchanged functions). The widest level that yields a 1:1 match wins,
narrower levels are only tried when the wider level is ambiguous.
find_twin_suffixed(): Uses already-correlated LLVM symbol pairs to map
.llvm.<hash> suffixes from orig to patched. Because all promoted
symbols from the same TU share the same hash, one correlated pair
seeds the mapping for the entire TU.
find_twin_positional(): Last resort, matches symbols by position among
same-named candidates, similar to livepatch sympos. Used for data
objects like __quirk variables where no deterministic filter can
distinguish the candidates.
Overall this works much better than the existing algorithm, particularly
with LTO kernels.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Start checksumming data objects in preparation for revamping the
correlation algorithm.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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The checksum functionality has been moved to "objtool klp checksum"
which is now used by klp-build. Remove the now-dead --checksum and
--debug-checksum options from the default objtool command.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Move the checksum functionality out of the main objtool command into a
new "objtool klp checksum" subcommand.
This has the benefit of making the code (and the patch generation
process itself) more modular.
For bisectability, both "objtool --checksum" and "objtool klp checksum"
work for now. The former will be removed after klp-build has been
converted to use the new subcommand.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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decode_sections() relies on CFI and cfi_hash initialization done
separately in check(), making it unusable outside of check().
Consolidate the initialization into decode_sections() and rename it to
decode_file(), and make it global along with free_insns() and
insn_reloc() for use by other objtool components -- namely, the checksum
code which will be moving to another file.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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In preparation for porting the checksum code to other arches, make its
functionality independent from the CFG reverse engineering code.
Move it into a standalone calculate_checksums() function which iterates
all functions and instructions directly, rather than being called inline
from do_validate_branch().
Since checksum_update_insn() is no longer called during CFG traversal,
it needs to manually iterate the alternatives.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Add an is_cold_func() helper. No functional changes intended.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Improve readability with a new is_alias_sym() helper.
No functional changes intended.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Clang generates anonymous data sections named .data..Lanon.<hash>.
These need section-symbol references in the same way as .data..Lubsan
(GCC) and .data..L__unnamed_ (Clang UBSAN) sections. Without this,
convert_reloc_sym() fails when processing relocations that reference
these sections.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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If an object file has no functions, objtool has nothing to checksum, so
it doesn't create the .discard.sym_checksum symbol.
Then when 'objtool klp diff' reads symbol checksums, it errors out due
to the missing .discard.sym_checksum section.
Instead, just create an empty checksum section to signal to
read_sym_checksums() that the file has been processed.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Instead of installing libsubcmd headers to a build output directory and
including from there, include directly from tools/lib/ where they
already exist. This fixes clangd indexing which otherwise can't find
libsubcmd headers.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Section symbols aren't grouped after their corresponding FILE symbols.
Their sym->file should really be NULL rather than whatever random FILE
happened to be last.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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In find_reloc_by_dest_range(), hash collisions can cause a high-offset
relocation to appear when probing a low-offset hash bucket.
Only return early when the best match found so far genuinely belongs to
the current bucket (its offset is within the bucket's stride range).
Otherwise, continue scanning later buckets which may contain
lower-offset matches.
This ensures the first reloc in the range gets returned.
Fixes: 74b873e49d92 ("objtool: Optimize find_rela_by_dest_range()")
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Use the section symbol's index instead of the old symbol's index when
updating the ELF relocation entry in convert_reloc_sym_to_secsym().
Found by Sashiko review.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Clang aggregates UBSAN type descriptors into shared anonymous
.data..L__unnamed_* sections. This data is used by UBSAN trap handlers.
When a changed function has an UBSAN bounds check, klp-diff clones the
entire UBSAN data section associated with the TU. Relocations within
the cloned section that reference named rodata objects in .rodata.cst*
(like 'exponent', 'pirq_ali_set.irqmap') become KLP relocations because
those objects now get correlated.
That results in a .klp.rela.vmlinux..data section which can easily have
thousands of KLP relocs, most of which are completely superfluous, used
by functions which aren't cloned to the patch module.
The .rodata.cst* sections are SHF_MERGE constant pool sections
containing small fixed-size data (lookup tables, bitmasks) that is only
read by value. Pointer identity is never relevant for these objects, so
correlating them is unnecessary.
Exclude .rodata.cst* objects from correlation so they get cloned as
local data instead of generating KLP relocations.
It might be possible to someday treat UBSAN data sections as special
sections, and only extract the few needed entries. But this works for
now.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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klp-diff treats all rodata as uncorrelated, so any reference to it uses
a duplicated copy rather than using a KLP reloc.
For the contents of the data itself, a duplicated copy is fine.
However, pointer comparisons (e.g., f->f_op == &foo_ops) are broken.
Fix it by correlating non-anonymous rodata objects.
Also, use a new find_symbol_containing_inclusive() helper for matching
the end of a symbol so bounds calculations don't get broken, for the
case where an array or other symbol's ending address is used as part of
a bounds calculation.
While these are really two distinct changes, they need to be done in the
same patch so as to avoid introducing bisection regressions.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Inline section_reference_needed() and is_reloc_allowed() into
convert_reloc_sym() and remove the redundant is_reloc_allowed() check in
clone_reloc().
Move the is_sec_sym() checks into the convert callees so they become
no-ops when the reloc is already in the right format. This allows
convert_reloc_sym() to unconditionally dispatch to the right converter
based on section type.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Move the sec->rodata marking from check.c to elf.c so it's set during
ELF reading rather than during the check pipeline. This makes the
rodata flag available to all objtool users, including klp-diff which
reads ELF files directly without running check().
Add an is_rodata_sec() helper to elf.h for consistency with
is_text_sec() and is_string_sec().
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Objtool has some hacks which NOP out certain calls/jumps and replace
their relocations with R_X86_64_NONE. The klp-diff relocation
extraction code will error out when trying to copy these relocations due
to their negative addend, which would only makes sense for a PC-relative
branch instruction. Just ignore them.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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.kcfi_traps contains references to kCFI trap instruction locations.
When a KCFI type check fails at an indirect call, the trap handler looks
up the faulting address in this section.
Add it to the special sections list so the entries get extracted for the
changed functions they reference.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Objtool is failing to extract text annotations which reference
.altinstr_replacement instructions:
1) Alternative replacement fake symbols are NOTYPE rather than FUNC,
and they don't have sym->included set, thus they aren't recognized
by should_keep_special_sym().
2) .discard.annotate_insn gets processed before .altinstr_replacement,
so the referenced (fake) symbols don't have clones yet.
Fix the first issue by checking for a valid clone instead of
sym->included and by accepting NOTYPE symbols when processing
.discard.annotate_insn.
Fix the second issue by deferring text annotation processing until after
the other special sections have been cloned.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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The XXH3 state allocated in checksum_init() is never freed. Free it in
checksum_finish().
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Fix NULL dereference when cloning a symbol from an empty section.
sec->data is only populated for sections with non-zero size.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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When a section is empty (e.g. only zero-length alternative
replacements), there are no symbols to convert a section symbol
reference to. Skip the reloc instead of erroring out.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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find_symbol_by_name() only returns the first match, so
--debug-checksum=<func> silently ignores any subsequent duplicately
named functions after the first.
Fix that, along with a new for_each_sym_by_name() helper.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Convert the callback-based iterate_sym_by_demangled_name() with a new
for_each_sym_by_demangled_name() macro. This eliminates the callback
struct/function and makes the code more compact and readable.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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create_fake_symbols() has two phases: creating symbols from
ANNOTATE_DATA_SPECIAL entries, and a fallback that uses sh_entsize for
special sections like .static_call_sites.
When .discard.annotate_data is absent, the function returns early,
skipping the entsize fallback and silently allowing unsupported
module-local static call keys through.
Fix it by jumping to the entsize phase instead of returning early.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Assisted-by: Claude:claude-4-opus
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Clang emits various .L-prefixed local symbols beyond .Ltmp*, such as
.L__const.* for local constant data. These are assembler-local labels
not present in kallsyms, so they can never be resolved at module load
time.
Broaden the check from .Ltmp* to all .L* symbols so they get cloned into
the patch module instead.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Clang LTO uses __UNIQUE_ID() to generate some uniquely named wrapper
functions, like initstubs. If they're uncorrelated, prevent them from
being reported as new functions and included unnecessarily.
Note that dont_correlate() already includes prefix functions, so prefix
functions are still being ignored here.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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With LTO, the initcall infrastructure generates __initstub__kmod_*
wrapper functions in .init.text. These are the LTO equivalent of
__initcall__kmod_* data pointers, which are already excluded from
correlation.
These are __init functions whose memory is freed after boot, so there's
no reason to include or reference them in a livepatch module.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Some arch/x86/crypto/*.S files define local .set/.equ constants that get
duplicated in vmlinux.o. This causes klp-diff to fail with "Multiple
correlation candidates" errors since it can't uniquely match these
between orig and patched builds.
Skip ABS symbols in dont_correlate(). They're purely compile-time
assembly constants that are never referenced by relocations, so they
don't need correlation.
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Symbols created by __ADDRESSABLE() are only used to convince the
toolchain not to optimize out the referenced symbol.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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While there was once a section named .data.once, it has since been
renamed to .data..once with commit dbefa1f31a91 ("Rename .data.once to
.data..once to fix resetting WARN*_ONCE"). Fix it.
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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For naming function-local static locals, GCC uses <var>.<id>, e.g.
__already_done.15, while Clang uses <func>.<var> with optional .<id>,
e.g. create_worker.__already_done.111
The existing is_uncorrelated_static_local() check only matches the GCC
convention where the variable name is a prefix. Handle both cases by
checking for a prefix match (GCC) and by checking after the first dot
separator (Clang).
Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
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Enhance vlmc_query_intvl_test and vlmc_query_response_intvl_test in
bridge_vlan_mcast.sh to validate IGMPv3/MLDv2 protocol compliance for
MRC and QQIC field encoding across both linear and exponential ranges.
TEST: Vlan multicast snooping enable [ OK ]
TEST: Vlan mcast_query_interval global option default value [ OK ]
TEST: Number of tagged IGMPv2 general query [ OK ]
TEST: IGMPv3 QQIC linear value 60(s) [ OK ]
TEST: MLDv2 QQIC linear value 60(s) [ OK ]
TEST: IGMPv3 QQIC non linear value 160(s) [ OK ]
TEST: MLDv2 QQIC non linear value 160(s) [ OK ]
TEST: Vlan mcast_query_response_interval global option default value [ OK ]
TEST: IGMPv3 MRC linear value of 60(x0.1s) [ OK ]
TEST: MLDv2 MRC linear value of 24000(ms) [ OK ]
TEST: IGMPv3 MRC non linear value of 240(x0.1s) [ OK ]
TEST: MLDv2 MRC non linear value of 48000(ms) [ OK ]
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Ujjal Roy <royujjal@gmail.com>
Link: https://patch.msgid.link/20260502131907.987-6-royujjal@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Add a single kselftest covering the proto_ops getsockopt_iter
conversions for AF_NETLINK and AF_VSOCK, using one fixture per protocol:
netlink:
NETLINK_PKTINFO covers the flag-style int path (exact size, oversize
clamp, undersize -EINVAL); NETLINK_LIST_MEMBERSHIPS covers the
size-discovery path that always reports the required buffer length back
via optlen, even when the user buffer is too small to receive any group
bits.
vsock:
SO_VM_SOCKETS_BUFFER_SIZE covers the u64 path (exact size, oversize
clamp, undersize -EINVAL).
Each fixture also exercises an unknown optname and a bogus level so
the returned-length / errno semantics preserved by the sockopt_t
conversion are pinned down.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20260501-getsock_one-v1-3-810ce23ea70e@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The L3 CAT test loads a buffer into cache that is proportional to the L3
size allocated for the workload and measures cache misses when accessing
the buffer as a test of L3 occupancy. When loading the buffer it can be
assumed that a portion of the buffer will be loaded into the L2 cache and
depending on cache design may not be present in L3. It is thus possible
for data to not be in L3 but also not trigger an L3 cache miss when
accessed.
Reduce impact of L2 on the L3 CAT test by, if L2 allocation is supported,
minimizing the portion of L2 that the workload can allocate into. This
encourages most of buffer to be loaded into L3 and support better
comparison between buffer size, cache portion, and cache misses when
accessing the buffer.
Link: https://lore.kernel.org/r/1f5aad318889cd6d4f9a8d8b0fbe83e3848d41a9.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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The CAT test relies on the PERF_COUNT_HW_CACHE_MISSES event to determine if
modifying a cache portion size is successful. This event is configured to
report the data as part of an event group, but no other events are added to
the group.
Remove the unnecessary PERF_FORMAT_GROUP format setting. This eliminates
the need for struct perf_event_read and results in read() of the associated
file descriptor to return just one value associated with the
PERF_COUNT_HW_CACHE_MISSES event of interest.
Link: https://lore.kernel.org/r/fb69325eba5031b735fa79effaaacd797c9c6040.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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As the CAT test reads the same buffer into different sized cache portions
it compares the number of cache misses against an expected percentage
based on the size of the cache portion.
Systems and test conditions vary. The CAT test is a test of resctrl
subsystem health and not a test of the hardware architecture so it is not
required to place requirements on the size of the difference in cache
misses, just that the number of cache misses when reading a buffer
increase as the cache portion used for the buffer decreases.
Remove additional constraint on how big the difference between cache
misses should be as the cache portion size changes. Only test that the
cache misses increase as the cache portion size decreases. This remains
a good sanity check of resctrl subsystem health while reducing impact
of hardware architectural differences and the various conditions under
which the test may run.
Increase the size difference between cache portions to additionally avoid
any consequences resulting from smaller increments.
Link: https://lore.kernel.org/r/6de4da5486354c0f25fef0d194956470cb744041.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Commit 501cfdba0a40 ("selftests/resctrl: Do not compare performance
counters and resctrl at low bandwidth") introduced a threshold under which
memory bandwidth values from MBM and performance counters are not compared.
This is needed because MBM and the PMUs do not have an identical view of
memory bandwidth since PMUs can count all memory traffic while MBM does not
count "overhead" (for example RAS) traffic that cannot be attributed to an
RMID. As a ratio this difference in view of memory bandwidth is pronounced
at low memory bandwidths.
The 750MiB threshold was chosen arbitrarily after comparisons on different
platforms. Exposed to more platforms after introduction this threshold has
proven to be inadequate.
Having accurate comparison between performance counters and MBM requires
careful management of system load as well as control of features that
introduce extra memory traffic, for example, patrol scrub. This is not
appropriate for the resctrl selftests that are intended to run on a
variety of systems with various configurations.
Increase the memory bandwidth threshold under which no comparison is made
between performance counters and MBM. Add additional leniency by increasing
the percentage of difference that will be tolerated between these counts.
There is no impact to the validity of the resctrl selftests results as a
measure of resctrl subsystem health.
Link: https://lore.kernel.org/r/b374c33ddd324130d6255cbb91c3dd500e8277e7.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Errata for Sierra Forest [1] (SRF42) and Granite Rapids [2] (GNR12)
describe the problem that MBM on Intel RDT may overcount memory bandwidth
measurements. The resctrl tests compare memory bandwidth reported by iMC
PMU to that reported by MBM causing the tests to fail on these systems
depending on the settings of the platform related to the errata.
Since the resctrl tests need to run under various conditions it is not
possible to ensure system settings are such that MBM will not overcount.
It has been observed that the overcounting can be controlled via the
buffer size used in the MBM and MBA tests that rely on comparisons
between iMC PMU and MBM measurements.
Running the MBM test on affected platforms with different buffer sizes it
can be observed that the difference between iMC PMU and MBM counts reduce
as the buffer size increases. After increasing the buffer size to more
than 4X the differences between iMC PMU and MBM become insignificant.
Increase the buffer size used in MBM and MBA tests to 4X L3 size to reduce
possibility of tests failing due to difference in counts reported by iMC
PMU and MBM.
Link: https://lore.kernel.org/r/1bd4d8c5fc791234b0a9da94f29a3e278ba2f7ee.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://edc.intel.com/content/www/us/en/design/products-and-solutions/processors-and-chipsets/sierra-forest/xeon-6700-series-processor-with-e-cores-specification-update/errata-details/ # [1]
Link: https://edc.intel.com/content/www/us/en/design/products-and-solutions/processors-and-chipsets/birch-stream/xeon-6900-6700-6500-series-processors-with-p-cores-specification-update/011US/errata-details/ # [2]
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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The resctrl selftests discover needed parameters to perf_event_open() via
sysfs. The PMU associated with every memory controller (iMC) is discovered
via the /sys/bus/event_source/devices/uncore_imc_N/type file while
the read memory bandwidth event type and umask is discovered via
/sys/bus/event_source/devices/uncore_imc_N/events/cas_count_read.
Newer systems may have multiple events that expose read memory bandwidth.
Running a recent kernel that includes
commit 6a8a48644c4b ("perf/x86/intel/uncore: Add per-scheduler IMC CAS count events")
on these systems expose the multiple events. For example,
/sys/bus/event_source/devices/uncore_imc_N/events/cas_count_read_sch0
/sys/bus/event_source/devices/uncore_imc_N/events/cas_count_read_sch1
Support parsing of iMC PMU properties when the PMU may have multiple events
to measure read memory bandwidth. The PMU only needs to be discovered once.
Split the parsing of event details from actual PMU discovery in order to
loop over all events associated with the PMU. Match all events with the
cas_count_read prefix instead of requiring there to be one file with that
name.
Make the parsing code more robust. With strings passed around to create
needed paths, use snprintf() instead of sprintf() to ensure there is
always enough space to create the path while using the standard PATH_MAX
for path lengths. Ensure there is enough room in imc_counters_config[]
before attempting to add an entry.
Link: https://lore.kernel.org/r/b03ca0fa21a09500c56ee589e32516c2c5effeaf.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Zide Chen <zide.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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The events needed to read memory bandwidth are discovered by iterating
over every memory controller (iMC) within /sys/bus/event_source/devices.
Each iMC's PMU is assumed to have one event to measure read memory
bandwidth that is represented by the sysfs cas_count_read file. The event's
configuration is read from "cas_count_read" and stored as an element of
imc_counters_config[] by read_from_imc_dir() that receives the
index of the array where to store the configuration as argument.
It is possible that an iMC's PMU may have more than one event that should
be used to measure memory bandwidth.
Change semantics to not provide the index of the array to
read_from_imc_dir() but instead a pointer to the index. This enables
read_from_imc_dir() to store configurations for more than one event by
incrementing the index to imc_counters_config[] itself.
Ensure that the same type is consistently used for the index as it is
passed around during counter configuration.
Link: https://lore.kernel.org/r/549e026d20af0381349e645c912e6470fce8bd7e.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Zide Chen <zide.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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The MBM and MBA tests compare MBM memory bandwidth measurements against
the memory bandwidth event values obtained from each memory controller's
PMU. The memory bandwidth event settings are discovered from the memory
controller details found in /sys/bus/event_source/devices/uncore_imc_N and
stored in struct imc_counter_config.
In addition to event settings struct imc_counter_config contains
imc_counter_config::return_value in which the associated event value is
stored on every read.
The event value is consumed and immediately recorded at regular intervals.
The stored value is never consumed afterwards, making its storage as part
of event configuration unnecessary.
Remove the return_value member from struct imc_counter_config. Instead
just use a more aptly named "measurement" local variable for use during
event reading.
Link: https://lore.kernel.org/r/e0b6ad2755e2fd802f54b0bc07eeb90247baca19.1775266384.git.reinette.chatre@intel.com
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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occupancy test
The CMT test creates a new control group that is also capable of monitoring
and assigns the workload to it. The workload allocates a buffer that by
default fills a portion of the L3 and keeps reading from the buffer,
measuring the L3 occupancy at intervals. The test passes if the workload's
L3 occupancy is within 15% of the buffer size.
The CMT test does not take into account that some of the workload's data
may land in L2/L1. Matching L3 occupancy to the size of the buffer while
a portion of the buffer can be allocated into L2 is not accurate.
Take the L2 cache into account to improve test accuracy:
- Reduce the workload's L2 cache allocation to the minimum on systems that
support L2 cache allocation. Do so with a new utility in preparation for
all L3 cache allocation tests needing the same capability.
- Increase the buffer size to accommodate data that may be allocated into
the L2 cache. Use a buffer size double the L3 portion to keep using the
L3 portion size as goal for L3 occupancy while taking into account that
some of the data may be in L2.
Running the CMT test on a sample system while introducing significant
cache misses using "stress-ng --matrix-3d 0 --matrix-3d-zyx" shows
significant improvement in L3 cache occupancy:
Before:
# Starting CMT test ...
# Mounting resctrl to "/sys/fs/resctrl"
# Cache size :335544320
# Writing benchmark parameters to resctrl FS
# Write schema "L3:0=fffe0" to resctrl FS
# Write schema "L3:0=1f" to resctrl FS
# Benchmark PID: 7089
# Checking for pass/fail
# Pass: Check cache miss rate within 15%
# Percent diff=12
# Number of bits: 5
# Average LLC val: 73269248
# Cache span (bytes): 83886080
ok 1 CMT: test
After:
# Starting CMT test ...
# Mounting resctrl to "/sys/fs/resctrl"
# Cache size :335544320
# Writing benchmark parameters to resctrl FS
# Write schema "L3:0=fffe0" to resctrl FS
# Write schema "L3:0=1f" to resctrl FS
# Write schema "L2:1=0x1" to resctrl FS
# Benchmark PID: 7171
# Checking for pass/fail
# Pass: Check cache miss rate within 15%
# Percent diff=0
# Number of bits: 5
# Average LLC val: 83755008
# Cache span (bytes): 83886080
ok 1 CMT: test
Link: https://lore.kernel.org/r/00445fa64c251b86b86023f87220ee1ad8561460.1775266384.git.reinette.chatre@intel.com
Reported-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/lkml/aO+7MeSMV29VdbQs@e133380.arm.com/
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Dave Martin reported inconsistent CMT test failures. In one experiment
the first run of the CMT test failed because of too large (24%) difference
between measured and achievable cache occupancy while the second run passed
with an acceptable 4% difference.
The CMT test is susceptible to interference from the rest of the system.
This can be demonstrated with a utility like stress-ng by running the CMT
test while introducing cache misses using:
stress-ng --matrix-3d 0 --matrix-3d-zyx
Below shows an example of the CMT test failing because of a significant
difference between measured and achievable cache occupancy when run with
interference:
# Starting CMT test ...
# Mounting resctrl to "/sys/fs/resctrl"
# Cache size :335544320
# Writing benchmark parameters to resctrl FS
# Benchmark PID: 7011
# Checking for pass/fail
# Fail: Check cache miss rate within 15%
# Percent diff=99
# Number of bits: 5
# Average LLC val: 235929
# Cache span (bytes): 83886080
not ok 1 CMT: test
The CMT test creates a new control group that is also capable of monitoring
and assigns the workload to it. The workload allocates a buffer that by
default fills a portion of the L3 and keeps reading from the buffer,
measuring the L3 occupancy at intervals. The test passes if the workload's
L3 occupancy is within 15% of the buffer size.
By not adjusting any capacity bitmasks the workload shares the cache with
the rest of the system. Any other task that may be running could evict
the workload's data from the cache causing it to have low cache occupancy.
Reduce interference from the rest of the system by ensuring that the
workload's control group uses the capacity bitmask found in the user
parameters for L3 and that the rest of the system can only allocate into
the inverse of the workload's L3 cache portion. Other tasks can thus no
longer evict the workload's data from L3.
With the above adjustments the CMT test is more consistent. Repeating the
CMT test while generating interference with stress-ng on a sample
system after applying the fixes show significant improvement in test
accuracy:
# Starting CMT test ...
# Mounting resctrl to "/sys/fs/resctrl"
# Cache size :335544320
# Writing benchmark parameters to resctrl FS
# Write schema "L3:0=fffe0" to resctrl FS
# Write schema "L3:0=1f" to resctrl FS
# Benchmark PID: 7089
# Checking for pass/fail
# Pass: Check cache miss rate within 15%
# Percent diff=12
# Number of bits: 5
# Average LLC val: 73269248
# Cache span (bytes): 83886080
ok 1 CMT: test
Link: https://lore.kernel.org/r/b160592179f88069cdc679563e152007998a0d76.1775266384.git.reinette.chatre@intel.com
Reported-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/lkml/aO+7MeSMV29VdbQs@e133380.arm.com/
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull kselftest fixes from Shuah Khan:
- Fix extra test number increment in ksft_exit_skip() that results in
incorrect KTAP result
- Fix regression introduced by addition of explicit constructor orders
for fixture tests. This addition broke the ordering of those relative
to non-fixture tests and the reverse-constructor-order detection
* tag 'linux_kselftest-fixes-7.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests: harness: Restore order of test functions
selftests: kselftest: fix wrong test number in ksft_exit_skip
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The second stage of test.sh ("run baseline data traffic") performs a
basic connectivity check with ping -qfc 500 -w 3. On slower CI
instances this is too strict for TCP: the RTT is high enough that 500
echo requests do not reliably complete within 3 seconds, so the stage
flakes and the test fails even though the ovpn setup is healthy.
Reduce the packet count to 100 for both the plain and 3000-byte pings in
that stage. This still verifies peer setup, key exchange, routing, and
data-path traffic, without making the basic connectivity check depend on
timing out under load.
Fixes: 959bc330a439 ("testing/selftests: add test tool and scripts for ovpn module")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
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Fix two spelling mistakes in kunit tooling:
Bascially -> Basically
higer -> higher
Link: https://lore.kernel.org/r/20260501162739.3861-1-always.starving0@gmail.com
Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
Reviewed-by: David Gow <david@davidgow.net>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Add a basic configuration to run kunit tests on or1k / openrisc.
Link: https://lore.kernel.org/r/20260427-kunit-or1k-v1-2-9d3109e991e8@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: David Gow <david@davidgow.net>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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