[ Upstream commit 1416270f4a1ae83ea84156ceba19a66a8f88be1f ] In the past we've warned when ADJ_OFFSET was in progress, usually caused by ntpd or some other time adjusting daemon running in non steady sate, which can cause the skew calculations to be incorrect. Thus, this patch checks to see if the clock was being adjusted when we fail so that we don't cause false negatives. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Miroslav Lichvar <mlichvar@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: linux-kselftest@vger.kernel.org Suggested-by: Miroslav Lichvar <mlichvar@redhat.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 86503bd35dec0ce363e9fdbf5299927422ed3899 upstream. Fix a bug in the key delete code - the num_records range from 0 to num_records-1. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reported-by: David Binderman <dcb314@hotmail.com> Cc: <stable@vger.kernel.org> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit c715fcfda5a08edabaa15508742be926b7ee51db ]
For powerpc64, redundant entries in the callchain are filtered out by
determining the state of the return address and the stack frame using
DWARF debug information.
For making these filtering decisions we must analyze the debug
information for the location corresponding to the program counter value,
i.e. the first entry in the callchain, and not the LR value; otherwise,
perf may filter out either the second or the third entry in the
callchain incorrectly.
This can be observed on a powerpc64le system running Fedora 27 as shown
below.
Case 1 - Attaching a probe at inet_pton+0x8 (binary offset 0x15af28).
Return address is still in LR and a new stack frame is not yet
allocated. The LR value, i.e. the second entry, should not be
filtered out.
# objdump -d /usr/lib64/libc-2.26.so | less
...
000000000010eb10 <gaih_inet.constprop.7>:
...
10fa48: 78 bb e4 7e mr r4,r23
10fa4c: 0a 00 60 38 li r3,10
10fa50: d9 b4 04 48 bl 15af28 <inet_pton+0x8>
10fa54: 00 00 00 60 nop
10fa58: ac f4 ff 4b b 10ef04 <gaih_inet.constprop.7+0x3f4>
...
0000000000110450 <getaddrinfo>:
...
1105a8: 54 00 ff 38 addi r7,r31,84
1105ac: 58 00 df 38 addi r6,r31,88
1105b0: 69 e5 ff 4b bl 10eb18 <gaih_inet.constprop.7+0x8>
1105b4: 78 1b 71 7c mr r17,r3
1105b8: 50 01 7f e8 ld r3,336(r31)
...
000000000015af20 <inet_pton>:
15af20: 0b 00 4c 3c addis r2,r12,11
15af24: e0 c1 42 38 addi r2,r2,-15904
15af28: a6 02 08 7c mflr r0
15af2c: f0 ff c1 fb std r30,-16(r1)
15af30: f8 ff e1 fb std r31,-8(r1)
...
# perf probe -x /usr/lib64/libc-2.26.so -a inet_pton+0x8
# perf record -e probe_libc:inet_pton -g ping -6 -c 1 ::1
# perf script
Before:
ping 4507 [002] 514985.546540: probe_libc:inet_pton: (7fffa7dbaf28)
7fffa7dbaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so)
7fffa7d705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so)
13fb52d70 _init+0xbfc (/usr/bin/ping)
7fffa7c836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
7fffa7c83898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
0 [unknown] ([unknown])
After:
ping 4507 [002] 514985.546540: probe_libc:inet_pton: (7fffa7dbaf28)
7fffa7dbaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so)
7fffa7d6fa54 gaih_inet.constprop.7+0xf44 (/usr/lib64/libc-2.26.so)
7fffa7d705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so)
13fb52d70 _init+0xbfc (/usr/bin/ping)
7fffa7c836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
7fffa7c83898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
0 [unknown] ([unknown])
Case 2 - Attaching a probe at _int_malloc+0x180 (binary offset 0x9cf10).
Return address in still in LR and a new stack frame has already
been allocated but not used. The caller's caller, i.e. the third
entry, is invalid and should be filtered out and not the second
one.
# objdump -d /usr/lib64/libc-2.26.so | less
...
000000000009cd90 <_int_malloc>:
9cd90: 17 00 4c 3c addis r2,r12,23
9cd94: 70 a3 42 38 addi r2,r2,-23696
9cd98: 26 00 80 7d mfcr r12
9cd9c: f8 ff e1 fb std r31,-8(r1)
9cda0: 17 00 e4 3b addi r31,r4,23
9cda4: d8 ff 61 fb std r27,-40(r1)
9cda8: 78 23 9b 7c mr r27,r4
9cdac: 1f 00 bf 2b cmpldi cr7,r31,31
9cdb0: f0 ff c1 fb std r30,-16(r1)
9cdb4: b0 ff c1 fa std r22,-80(r1)
9cdb8: 78 1b 7e 7c mr r30,r3
9cdbc: 08 00 81 91 stw r12,8(r1)
9cdc0: 11 ff 21 f8 stdu r1,-240(r1)
9cdc4: 4c 01 9d 41 bgt cr7,9cf10 <_int_malloc+0x180>
9cdc8: 20 00 a4 2b cmpldi cr7,r4,32
...
9cf08: 00 00 00 60 nop
9cf0c: 00 00 42 60 ori r2,r2,0
9cf10: e4 06 ff 7b rldicr r31,r31,0,59
9cf14: 40 f8 a4 7f cmpld cr7,r4,r31
9cf18: 68 05 9d 41 bgt cr7,9d480 <_int_malloc+0x6f0>
...
000000000009e3c0 <tcache_init.part.4>:
...
9e420: 40 02 80 38 li r4,576
9e424: 78 fb e3 7f mr r3,r31
9e428: 71 e9 ff 4b bl 9cd98 <_int_malloc+0x8>
9e42c: 00 00 a3 2f cmpdi cr7,r3,0
9e430: 78 1b 7e 7c mr r30,r3
...
000000000009f7a0 <__libc_malloc>:
...
9f8f8: 00 00 89 2f cmpwi cr7,r9,0
9f8fc: 1c ff 9e 40 bne cr7,9f818 <__libc_malloc+0x78>
9f900: c9 ea ff 4b bl 9e3c8 <tcache_init.part.4+0x8>
9f904: 00 00 00 60 nop
9f908: e8 90 22 e9 ld r9,-28440(r2)
...
# perf probe -x /usr/lib64/libc-2.26.so -a _int_malloc+0x180
# perf record -e probe_libc:_int_malloc -g ./test-malloc
# perf script
Before:
test-malloc 6554 [009] 515975.797403: probe_libc:_int_malloc: (7fffa6e6cf10)
7fffa6e6cf10 _int_malloc+0x180 (/usr/lib64/libc-2.26.so)
7fffa6dd0000 [unknown] (/usr/lib64/libc-2.26.so)
7fffa6e6f904 malloc+0x164 (/usr/lib64/libc-2.26.so)
7fffa6e6f9fc malloc+0x25c (/usr/lib64/libc-2.26.so)
100006b4 main+0x38 (/home/testuser/test-malloc)
7fffa6df36a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
7fffa6df3898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
0 [unknown] ([unknown])
After:
test-malloc 6554 [009] 515975.797403: probe_libc:_int_malloc: (7fffa6e6cf10)
7fffa6e6cf10 _int_malloc+0x180 (/usr/lib64/libc-2.26.so)
7fffa6e6e42c tcache_init.part.4+0x6c (/usr/lib64/libc-2.26.so)
7fffa6e6f904 malloc+0x164 (/usr/lib64/libc-2.26.so)
7fffa6e6f9fc malloc+0x25c (/usr/lib64/libc-2.26.so)
100006b4 main+0x38 (/home/sandipan/test-malloc)
7fffa6df36a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
7fffa6df3898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
0 [unknown] ([unknown])
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Maynard Johnson <maynard@us.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Fixes: a60335ba3298 ("perf tools powerpc: Adjust callchain based on DWARF debug info")
Link: http://lkml.kernel.org/r/24bb726d91ed173aebc972ec3f41a2ef2249434e.1530724939.git.sandipan@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9068533e4f470daf2b0f29c71d865990acd8826e ]
For powerpc64, perf will filter out the second entry in the callchain,
i.e. the LR value, if the return address of the function corresponding
to the probed location has already been saved on its caller's stack.
The state of the return address is determined using debug information.
At any point within a function, if the return address is already saved
somewhere, a DWARF expression can tell us about its location. If the
return address in still in LR only, no DWARF expression would exist.
Typically, the instructions in a function's prologue first copy the LR
value to R0 and then pushes R0 on to the stack. If LR has already been
copied to R0 but R0 is yet to be pushed to the stack, we can still get a
DWARF expression that says that the return address is in R0. This is
indicating that getting a DWARF expression for the return address does
not guarantee the fact that it has already been saved on the stack.
This can be observed on a powerpc64le system running Fedora 27 as shown
below.
# objdump -d /usr/lib64/libc-2.26.so | less
...
000000000015af20 <inet_pton>:
15af20: 0b 00 4c 3c addis r2,r12,11
15af24: e0 c1 42 38 addi r2,r2,-15904
15af28: a6 02 08 7c mflr r0
15af2c: f0 ff c1 fb std r30,-16(r1)
15af30: f8 ff e1 fb std r31,-8(r1)
15af34: 78 1b 7f 7c mr r31,r3
15af38: 78 23 83 7c mr r3,r4
15af3c: 78 2b be 7c mr r30,r5
15af40: 10 00 01 f8 std r0,16(r1)
15af44: c1 ff 21 f8 stdu r1,-64(r1)
15af48: 28 00 81 f8 std r4,40(r1)
...
# readelf --debug-dump=frames-interp /usr/lib64/libc-2.26.so | less
...
00027024 0000000000000024 00027028 FDE cie=00000000 pc=000000000015af20..000000000015af88
LOC CFA r30 r31 ra
000000000015af20 r1+0 u u u
000000000015af34 r1+0 c-16 c-8 r0
000000000015af48 r1+64 c-16 c-8 c+16
000000000015af5c r1+0 c-16 c-8 c+16
000000000015af78 r1+0 u u
...
# perf probe -x /usr/lib64/libc-2.26.so -a inet_pton+0x18
# perf record -e probe_libc:inet_pton -g ping -6 -c 1 ::1
# perf script
Before:
ping 2829 [005] 512917.460174: probe_libc:inet_pton: (7fff7e2baf38)
7fff7e2baf38 __GI___inet_pton+0x18 (/usr/lib64/libc-2.26.so)
7fff7e2705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so)
12f152d70 _init+0xbfc (/usr/bin/ping)
7fff7e1836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
7fff7e183898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
0 [unknown] ([unknown])
After:
ping 2829 [005] 512917.460174: probe_libc:inet_pton: (7fff7e2baf38)
7fff7e2baf38 __GI___inet_pton+0x18 (/usr/lib64/libc-2.26.so)
7fff7e26fa54 gaih_inet.constprop.7+0xf44 (/usr/lib64/libc-2.26.so)
7fff7e2705b4 getaddrinfo+0x164 (/usr/lib64/libc-2.26.so)
12f152d70 _init+0xbfc (/usr/bin/ping)
7fff7e1836a0 generic_start_main.isra.0+0x140 (/usr/lib64/libc-2.26.so)
7fff7e183898 __libc_start_main+0xb8 (/usr/lib64/libc-2.26.so)
0 [unknown] ([unknown])
Reported-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Maynard Johnson <maynard@us.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/66e848a7bdf2d43b39210a705ff6d828a0865661.1530724939.git.sandipan@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 46b3722cc7765582354488da633aafffcb138458 ]
We occasionaly hit following assert failure in 'perf top', when processing the
/proc info in multiple threads.
perf: ...include/linux/refcount.h:109: refcount_inc:
Assertion `!(!refcount_inc_not_zero(r))' failed.
The gdb backtrace looks like this:
[Switching to Thread 0x7ffff11ba700 (LWP 13749)]
0x00007ffff50839fb in raise () from /lib64/libc.so.6
(gdb)
#0 0x00007ffff50839fb in raise () from /lib64/libc.so.6
#1 0x00007ffff5085800 in abort () from /lib64/libc.so.6
#2 0x00007ffff507c0da in __assert_fail_base () from /lib64/libc.so.6
#3 0x00007ffff507c152 in __assert_fail () from /lib64/libc.so.6
#4 0x0000000000535373 in refcount_inc (r=0x7fffdc009be0)
at ...include/linux/refcount.h:109
#5 0x00000000005354f1 in comm_str__get (cs=0x7fffdc009bc0)
at util/comm.c:24
#6 0x00000000005356bd in __comm_str__findnew (str=0x7fffd000b260 ":2",
root=0xbed5c0 <comm_str_root>) at util/comm.c:72
#7 0x000000000053579e in comm_str__findnew (str=0x7fffd000b260 ":2",
root=0xbed5c0 <comm_str_root>) at util/comm.c:95
#8 0x000000000053582e in comm__new (str=0x7fffd000b260 ":2",
timestamp=0, exec=false) at util/comm.c:111
#9 0x00000000005363bc in thread__new (pid=2, tid=2) at util/thread.c:57
#10 0x0000000000523da0 in ____machine__findnew_thread (machine=0xbfde38,
threads=0xbfdf28, pid=2, tid=2, create=true) at util/machine.c:457
#11 0x0000000000523eb4 in __machine__findnew_thread (machine=0xbfde38,
...
The failing assertion is this one:
REFCOUNT_WARN(!refcount_inc_not_zero(r), ...
The problem is that we keep global comm_str_root list, which
is accessed by multiple threads during the 'perf top' startup
and following 2 paths can race:
thread 1:
...
thread__new
comm__new
comm_str__findnew
down_write(&comm_str_lock);
__comm_str__findnew
comm_str__get
thread 2:
...
comm__override or comm__free
comm_str__put
refcount_dec_and_test
down_write(&comm_str_lock);
rb_erase(&cs->rb_node, &comm_str_root);
Because thread 2 first decrements the refcnt and only after then it removes the
struct comm_str from the list, the thread 1 can find this object on the list
with refcnt equls to 0 and hit the assert.
This patch fixes the thread 1 __comm_str__findnew path, by ignoring objects
that already dropped the refcnt to 0. For the rest of the objects we take the
refcnt before comparing its name and release it afterwards with comm_str__put,
which can also release the object completely.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Lukasz Odzioba <lukasz.odzioba@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20180720101740.GA27176@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e8fedff1cc729fd227924305152ccc6f580e8c83 ]
Stephan reported, that pipe mode does not carry the group information
and thus the piped report won't display the grouped output for following
command:
# perf record -e '{cycles,instructions,branches}' -a sleep 4 | perf report
It has no idea about the group setup, so it will display events
separately:
# Overhead Command Shared Object ...
# ........ ............... .......................
#
6.71% swapper [kernel.kallsyms]
2.28% offlineimap libpython2.7.so.1.0
0.78% perf [kernel.kallsyms]
...
Fix GROUP_DESC feature record to be synthesized in pipe mode, so the
report output is grouped if there are groups defined in record:
# Overhead Command Shared ...
# ........................ ............... .......
#
7.57% 0.16% 0.30% swapper [kernel
1.87% 3.15% 2.46% offlineimap libpyth
1.33% 0.00% 0.00% perf [kernel
...
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180712135202.14774-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 9ef0112442bdddef5fb55adf20b3a5464b33de75 ] Perf test 40 for example has several subtests numbered 1-4 when displaying the start of the subtest. When the subtest results are displayed the subtests are numbered 0-3. Use this command to generate trace output: [root@s35lp76 perf]# ./perf test -Fv 40 2>/tmp/bpf1 Fix this by adjusting the subtest number when show the subtest result. Output before: [root@s35lp76 perf]# egrep '(^40\.[0-4]| subtest [0-4]:)' /tmp/bpf1 40.1: Basic BPF filtering : BPF filter subtest 0: Ok 40.2: BPF pinning : BPF filter subtest 1: Ok 40.3: BPF prologue generation : BPF filter subtest 2: Ok 40.4: BPF relocation checker : BPF filter subtest 3: Ok [root@s35lp76 perf]# Output after: root@s35lp76 ~]# egrep '(^40\.[0-4]| subtest [0-4]:)' /tmp/bpf1 40.1: Basic BPF filtering : BPF filter subtest 1: Ok 40.2: BPF pinning : BPF filter subtest 2: Ok 40.3: BPF prologue generation : BPF filter subtest 3: Ok 40.4: BPF relocation checker : BPF filter subtest 4: Ok [root@s35lp76 ~]# Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Link: http://lkml.kernel.org/r/20180724134858.100644-1-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 45df5d3dc0c7289c1e67afe6d2ba806ad5174314 ] The mock / test version of pmem_direct_access() needs to check the validity of pointers kaddr and pfn for NULL assignment. If anyone equals to NULL, it doesn't need to calculate the value. If pointer equals to NULL, that is to say callers may have no need for kaddr or pfn, so this patch is prepared for allowing them to pass in NULL instead of having to pass in a local pointer or variable that they then just throw away. Suggested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Huaisheng Ye <yehs1@lenovo.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 95035c5e167ae6e740b1ddd30210ae0eaf39a5db ] 'perf record' will error out if both --delay and LBR are applied. For example: # perf record -D 1000 -a -e cycles -j any -- sleep 2 Error: dummy:HG: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat' # A dummy event is added implicitly for initial delay, which has the same configurations as real sampling events. The dummy event is a software event. If LBR is configured, perf must error out. The dummy event will only be used to track PERF_RECORD_MMAP while perf waits for the initial delay to enable the real events. The BRANCH_STACK bit can be safely cleared for the dummy event. After applying the patch: # perf record -D 1000 -a -e cycles -j any -- sleep 2 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 1.054 MB perf.data (828 samples) ] # Reported-by: Sunil K Pandey <sunil.k.pandey@intel.com> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1531145722-16404-1-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 73978332572ccf5e364c31e9a70ba953f8202b46 ]
'perf c2c' scans read/write accesses and tries to find false sharing
cases, so when the events it wants were not asked for or ended up not
taking place, we get no histograms.
So do not try to display entry details if there's not any. Currently
this ends up in crash:
$ perf c2c report # then press 'd'
perf: Segmentation fault
$
Committer testing:
Before:
Record a perf.data file without events of interest to 'perf c2c report',
then call it and press 'd':
# perf record sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.001 MB perf.data (6 samples) ]
# perf c2c report
perf: Segmentation fault
-------- backtrace --------
perf[0x5b1d2a]
/lib64/libc.so.6(+0x346df)[0x7fcb566e36df]
perf[0x46fcae]
perf[0x4a9f1e]
perf[0x4aa220]
perf(main+0x301)[0x42c561]
/lib64/libc.so.6(__libc_start_main+0xe9)[0x7fcb566cff29]
perf(_start+0x29)[0x42c999]
#
After the patch the segfault doesn't take place, a follow up patch to
tell the user why nothing changes when 'd' is pressed would be good.
Reported-by: rodia@autistici.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: f1c5fd4d0bb9 ("perf c2c report: Add TUI cacheline browser")
Link: http://lkml.kernel.org/r/20180724062008.26126-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>