linux-stable.git/tools/perf/util/machine.c, branch v5.8

perf tools: Fix is_bpf_image function logic

2020-05-28T13:03:26+00:00

Adrian reported that is_bpf_image is not working the way it was intended
- passing on trampolines and dispatcher names. Instead it returned true
for all the bpf names.

The reason even this logic worked properly is that all bpf objects, even
trampolines and dispatcher, were assigned DSO_BINARY_TYPE__BPF_IMAGE
binary_type.

The later for bpf_prog objects, the binary_type was fixed in bpf load
event processing, which is executed after the ksymbol code.

Fixing the is_bpf_image logic, so it properly recognizes trampoline and
dispatcher objects.

Fixes: 3c29d4483e85 ("perf annotate: Add basic support for bpf_image")
Reported-by: Adrian Hunter 
Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20200512122310.3154754-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Rename perf_evselenv() to evselenv()

2020-05-05T19:35:31+00:00

As it is a 'struct evsel' method, not part of tools/lib/perf/, aka
libperf, to whom the perf_ prefix belongs.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Rename perf_evselhas() to evselhas()

2020-05-05T19:35:31+00:00

As those are 'struct evsel' methods, not part of tools/lib/perf/, aka
libperf, to whom the perf_ prefix belongs.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Stitch LBR call stack

2020-04-18T12:05:01+00:00

In LBR call stack mode, the depth of reconstructed LBR call stack limits
to the number of LBR registers.

  For example, on skylake, the depth of reconstructed LBR call stack is
  always <= 32.

  # To display the perf.data header info, please use
  # --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 6K of event 'cycles'
  # Event count (approx.): 6487119731
  #
  # Children      Self  Command          Shared Object       Symbol
  # ........  ........  ...............  ..................
  # ................................

    99.97%    99.97%  tchain_edit      tchain_edit        [.] f43
            |
             --99.64%--f11
                       f12
                       f13
                       f14
                       f15
                       f16
                       f17
                       f18
                       f19
                       f20
                       f21
                       f22
                       f23
                       f24
                       f25
                       f26
                       f27
                       f28
                       f29
                       f30
                       f31
                       f32
                       f33
                       f34
                       f35
                       f36
                       f37
                       f38
                       f39
                       f40
                       f41
                       f42
                       f43

For a call stack which is deeper than LBR limit, HW will overwrite the
LBR register with oldest branch. Only partial call stacks can be
reconstructed.

However, the overwritten LBRs may still be retrieved from previous
sample. At that moment, HW hasn't overwritten the LBR registers yet.
Perf tools can stitch those overwritten LBRs on current call stacks to
get a more complete call stack.

To determine if LBRs can be stitched, perf tools need to compare current
sample with previous sample.

- They should have identical LBR records (Same from, to and flags
  values, and the same physical index of LBR registers).

- The searching starts from the base-of-stack of current sample.

Once perf determines to stitch the previous LBRs, the corresponding LBR
cursor nodes will be copied to 'lists'.  The 'lists' is to track the LBR
cursor nodes which are going to be stitched.

When the stitching is over, the nodes will not be freed immediately.
They will be moved to 'free_lists'. Next stitching may reuse the space.
Both 'lists' and 'free_lists' will be freed when all samples are
processed.

Committer notes:

Fix the intel-pt.c initialization of the union with 'struct
branch_flags', that breaks the build with its unnamed union on older gcc
versions.

Uninline thread__free_stitch_list(), as it grew big and started dragging
includes to thread.h, so move it to thread.c where what it needs in
terms of headers are already there.

This fixes the build in several systems such as debian:experimental when
cross building to the MIPS32 architecture, i.e. in the other cases what
was needed was being included by sheer luck.

  In file included from builtin-sched.c:11:
  util/thread.h: In function 'thread__free_stitch_list':
  util/thread.h:169:3: error: implicit declaration of function 'free' [-Werror=implicit-function-declaration]
    169 |   free(pos);
        |   ^~~~
  util/thread.h:169:3: error: incompatible implicit declaration of built-in function 'free' [-Werror]
  util/thread.h:19:1: note: include '' or provide a declaration of 'free'
     18 | #include "callchain.h"
    +++ |+#include 
     19 |
  util/thread.h:174:3: error: incompatible implicit declaration of built-in function 'free' [-Werror]
    174 |   free(pos);
        |   ^~~~
  util/thread.h:174:3: note: include '' or provide a declaration of 'free'

Signed-off-by: Kan Liang 
Reviewed-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexey Budankov 
Cc: Mathieu Poirier 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Pavel Gerasimov 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Stephane Eranian 
Cc: Vitaly Slobodskoy 
Link: http://lore.kernel.org/lkml/20200319202517.23423-13-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Save previous cursor nodes for LBR stitching approach

2020-04-18T12:05:01+00:00

The cursor nodes which generates from sample are eventually added into
callchain. To avoid generating cursor nodes from previous samples again,
the previous cursor nodes are also saved for LBR stitching approach.

Some option, e.g. hide-unresolved, may hide some LBRs.  Add a variable
'valid' in struct callchain_cursor_node to indicate this case. The LBR
stitching approach will only append the valid cursor nodes from previous
samples later.

Signed-off-by: Kan Liang 
Reviewed-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexey Budankov 
Cc: Mathieu Poirier 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Pavel Gerasimov 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Stephane Eranian 
Cc: Vitaly Slobodskoy 
Link: http://lore.kernel.org/lkml/20200319202517.23423-12-kan.liang@linux.intel.com
[ Use zfree() instead of open coded equivalent, and use it when freeing members of structs ]
Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Save previous sample for LBR stitching approach

2020-04-18T12:05:01+00:00

To retrieve the overwritten LBRs from previous sample for LBR stitching
approach, perf has to save the previous sample.

Only allocate the struct lbr_stitch once, when LBR stitching approach is
enabled and kernel supports hw_idx.

Signed-off-by: Kan Liang 
Reviewed-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexey Budankov 
Cc: Mathieu Poirier 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Pavel Gerasimov 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Stephane Eranian 
Cc: Vitaly Slobodskoy 
Link: http://lore.kernel.org/lkml/20200319202517.23423-11-kan.liang@linux.intel.com
[ Use zalloc()/zfree() for thread->lbr_stitch ]
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Factor out lbr_callchain_add_lbr_ip()

2020-04-18T12:05:01+00:00

Both caller and callee needs to add ip from LBR to callchain.
Factor out lbr_callchain_add_lbr_ip() to improve code readability.

Signed-off-by: Kan Liang 
Reviewed-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexey Budankov 
Cc: Mathieu Poirier 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Pavel Gerasimov 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Stephane Eranian 
Cc: Vitaly Slobodskoy 
Link: http://lore.kernel.org/lkml/20200319202517.23423-9-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Factor out lbr_callchain_add_kernel_ip()

2020-04-18T12:05:00+00:00

Both caller and callee needs to add kernel ip to callchain.  Factor out
lbr_callchain_add_kernel_ip() to improve code readability.

Signed-off-by: Kan Liang 
Reviewed-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexey Budankov 
Cc: Mathieu Poirier 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Pavel Gerasimov 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Stephane Eranian 
Cc: Vitaly Slobodskoy 
Link: http://lore.kernel.org/lkml/20200319202517.23423-8-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Refine the function for LBR call stack reconstruction

2020-04-18T12:05:00+00:00

LBR only collect the user call stack. To reconstruct a call stack, both
kernel call stack and user call stack are required. The function
resolve_lbr_callchain_sample() mix the kernel call stack and user call
stack.

Now, with the help of HW idx, perf tool can reconstruct a more complete
call stack by adding some user call stack from previous sample. However,
current implementation is hard to be extended to support it.

Current code path for resolve_lbr_callchain_sample()

  for (j = 0; j < mix_chain_nr; j++) {
       if (ORDER_CALLEE) {
             if (kernel callchain)
                  Fill callchain info
             else if (LBR callchain)
                  Fill callchain info
       } else {
             if (LBR callchain)
                  Fill callchain info
             else if (kernel callchain)
                  Fill callchain info
       }
       add_callchain_ip();
  }

With the patch,

  if (ORDER_CALLEE) {
       for (j = 0; j < NUM of kernel callchain) {
             Fill callchain info
             add_callchain_ip();
       }
       for (; j < mix_chain_nr) {
             Fill callchain info
             add_callchain_ip();
       }
  } else {
       for (; j < NUM of LBR callchain) {
             Fill callchain info
             add_callchain_ip();
       }
       for (j = 0; j < mix_chain_nr) {
             Fill callchain info
             add_callchain_ip();
       }
  }

No functional changes.

Signed-off-by: Kan Liang 
Reviewed-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexey Budankov 
Cc: Mathieu Poirier 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Pavel Gerasimov 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Stephane Eranian 
Cc: Vitaly Slobodskoy 
Link: http://lore.kernel.org/lkml/20200319202517.23423-7-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Remove the indent in resolve_lbr_callchain_sample

2020-04-18T12:05:00+00:00

The indent is unnecessary in resolve_lbr_callchain_sample.  Removing it
will make the following patch simpler.

Current code path for resolve_lbr_callchain_sample()

        /* LBR only affects the user callchain */
        if (i != chain_nr) {
                body of the function
                ....
                return 1;
        }

        return 0;

With the patch,

        /* LBR only affects the user callchain */
        if (i == chain_nr)
                return 0;

        body of the function
        ...
        return 1;

No functional changes.

Signed-off-by: Kan Liang 
Reviewed-by: Andi Kleen 
Acked-by: Jiri Olsa 
Cc: Adrian Hunter 
Cc: Alexey Budankov 
Cc: Mathieu Poirier 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Pavel Gerasimov 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Stephane Eranian 
Cc: Vitaly Slobodskoy 
Link: http://lore.kernel.org/lkml/20200319202517.23423-6-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo

linux-stable.git/tools/perf/util/machine.c, branch v5.8

perf tools: Fix is_bpf_image function logic

perf evsel: Rename perf_evsel__env() to evsel__env()

perf evsel: Rename perf_evsel__has*() to evsel__has*()

perf callchain: Stitch LBR call stack

perf callchain: Save previous cursor nodes for LBR stitching approach

perf thread: Save previous sample for LBR stitching approach

perf machine: Factor out lbr_callchain_add_lbr_ip()

perf machine: Factor out lbr_callchain_add_kernel_ip()

perf machine: Refine the function for LBR call stack reconstruction

perf machine: Remove the indent in resolve_lbr_callchain_sample

perf evsel: Rename perf_evselenv() to evselenv()

perf evsel: Rename perf_evselhas() to evselhas()