Re: [PATCH v2 06/18] perf s390 s390_cpumcfdg_dump: Don't scan all PMUs

From: Arnaldo Carvalho de Melo
Date: Tue Aug 29 2023 - 07:29:57 EST


Em Mon, Aug 28, 2023 at 05:59:47PM -0700, Ian Rogers escreveu:
> On Mon, Aug 28, 2023 at 10:53 AM Arnaldo Carvalho de Melo
> <acme@xxxxxxxxxx> wrote:
> >
> > Em Mon, Aug 28, 2023 at 02:44:53PM -0300, Arnaldo Carvalho de Melo escreveu:
> > > Em Fri, Aug 25, 2023 at 03:56:54PM -0700, Ian Rogers escreveu:
> > > > On Fri, Aug 25, 2023 at 1:56 PM Arnaldo Carvalho de Melo
> > > > <acme@xxxxxxxxxx> wrote:
> > > > >
> > > > > Em Fri, Aug 25, 2023 at 04:39:22PM +0200, Thomas Richter escreveu:
> > > > > > On 8/25/23 15:14, Ian Rogers wrote:
> > > > > > > On Fri, Aug 25, 2023 at 1:20 AM Thomas Richter <tmricht@xxxxxxxxxxxxx> wrote:
> > > > >
> > > > > > >> On 8/24/23 15:59, Arnaldo Carvalho de Melo wrote:
> > > > > > >>> Em Wed, Aug 23, 2023 at 09:13:18PM -0700, Ian Rogers escreveu:
> > > > > > >>>> Rather than scanning all PMUs for a counter name, scan the PMU
> > > > > > >>>> associated with the evsel of the sample. This is done to remove a
> > > > > > >>>> dependence on pmu-events.h.
> > > > >
> > > > > > >>> I'm applying this one, and CCing the S/390 developers so that they can
> > > > > > >>> try this and maybe provide an Acked-by/Tested-by,
> > > > >
> > > > > > >> I have downloaded this patch set of 18 patches (using b4), but they do not
> > > > > > >> apply on my git tree.
> > > > >
> > > > > > >> Which git branch do I have to use to test this. Thanks a lot.
> > > > >
> > > > > > > the changes are in the perf-tools-next tree:
> > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/
> > > > >
> > > > > > Unfurtunately this patch set fails again on s390.
> > > > > > Here is the test output from the current 6.5.0rc7 kernel:
> > > > > >
> > > > > > # ./perf test 6 10 'perf all metricgroups test' 'perf all metrics test'
> > > > > > 6: Parse event definition strings :
> > > > > > 6.1: Test event parsing : Ok
> > > > > > 6.2: Parsing of all PMU events from sysfs : Ok
> > > > > > 6.3: Parsing of given PMU events from sysfs : Ok
> > > > > > 6.4: Parsing of aliased events from sysfs : Skip (no aliases in sysfs)
> > > > > > 6.5: Parsing of aliased events : Ok
> > > > > > 6.6: Parsing of terms (event modifiers) : Ok
> > > > > > 10: PMU events :
> > > > > > 10.1: PMU event table sanity : Ok
> > > > > > 10.2: PMU event map aliases : Ok
> > > > > > 10.3: Parsing of PMU event table metrics : Ok
> > > > > > 10.4: Parsing of PMU event table metrics with fake PMUs : Ok
> > > > > > 10.5: Parsing of metric thresholds with fake PMUs : Ok
> > > > > > 95: perf all metricgroups test : Ok
> > > > > > 96: perf all metrics test : Ok
> > > > > > #
> > > > > >
> > > > > > This looks good.
> > > > >
> > > > > Reproduced:
> > > > >
> > > > > # grep -E vendor_id\|^processor -m2 /proc/cpuinfo
> > > > > vendor_id : IBM/S390
> > > > > processor 0: version = 00, identification = 1A33E8, machine = 2964
> > > > > #
> > > > > # perf test 6 10 'perf all metricgroups test' 'perf all metrics test'
> > > > > 6: Parse event definition strings :
> > > > > 6.1: Test event parsing : Ok
> > > > > 6.2: Parsing of all PMU events from sysfs : Ok
> > > > > 6.3: Parsing of given PMU events from sysfs : Ok
> > > > > 6.4: Parsing of aliased events from sysfs : Skip (no aliases in sysfs)
> > > > > 6.5: Parsing of aliased events : Ok
> > > > > 6.6: Parsing of terms (event modifiers) : Ok
> > > > > 10: PMU events :
> > > > > 10.1: PMU event table sanity : Ok
> > > > > 10.2: PMU event map aliases : Ok
> > > > > 10.3: Parsing of PMU event table metrics : Ok
> > > > > 10.4: Parsing of PMU event table metrics with fake PMUs : Ok
> > > > > 10.5: Parsing of metric thresholds with fake PMUs : Ok
> > > > > 95: perf all metricgroups test : Ok
> > > > > 96: perf all metrics test : Ok
> > > > > # perf -v
> > > > > perf version 6.5.rc7.g6f0edbb833ec
> > > > > #
> > > > >
> > > > > > However when I use the check-out from perf-tools-next, I get this output:
> > > > > > # ./perf test 6 10 'perf all metricgroups test' 'perf all metrics test'
> > > > > > 6: Parse event definition strings :
> > > > > > 6.1: Test event parsing : Ok
> > > > > > 6.2: Parsing of all PMU events from sysfs : FAILED!
> > > > > > 6.3: Parsing of given PMU events from sysfs : Ok
> > > > > > 6.4: Parsing of aliased events from sysfs : Skip (no aliases in sysfs)
> > > > > > 6.5: Parsing of aliased events : FAILED!
> > > > > > 6.6: Parsing of terms (event modifiers) : Ok
> > > > > > 10: PMU events :
> > > > > > 10.1: PMU event table sanity : Ok
> > > > > > 10.2: PMU event map aliases : FAILED!
> > > > > > 10.3: Parsing of PMU event table metrics : Ok
> > > > > > 10.4: Parsing of PMU event table metrics with fake PMUs : FAILED!
> > > > > > 10.5: Parsing of metric thresholds with fake PMUs : Ok
> > > > > > 93: perf all metricgroups test : FAILED!
> > > > > > 94: perf all metrics test : FAILED!
> > > > > > #
> > > > > >
> > > > > > So some tests are failing again.
> > > > > >
> > > > > > I am out for the next two weeks, Sumanth Korikkar (on to list) might be able to help.
> > > > > > Thanks a lot.
> > > > >
> > > > > [root@kernelqe3 linux]# git checkout perf-tools-next
> > > > > git Switched to branch 'perf-tools-next'
> > > > > Your branch is up to date with 'perf-tools-next/perf-tools-next'.
> > > > > [root@kernelqe3 linux]# git log --oneline -5
> > > > > eeb6b12992c4 (HEAD -> perf-tools-next, perf-tools-next/perf-tools-next) perf jevents: Don't append Unit to desc
> > > > > f208b2c6f984 (perf-tools-next/tmp.perf-tools-next) perf scripts python gecko: Launch the profiler UI on the default browser with the appropriate URL
> > > > > 43803cb16f99 perf scripts python: Add support for input args in gecko script
> > > > > f85d120c46e7 perf jevents: Sort strings in the big C string to reduce faults
> > > > > 8d4b6d37ea78 perf pmu: Lazily load sysfs aliases
> > > > > [root@kernelqe3 linux]# make BUILD_BPF_SKEL=1 -C tools/perf O=/tmp/build/perf install-bin
> > > > >
> > > > > [root@kernelqe3 linux]# perf -v
> > > > > perf version 6.5.rc5.geeb6b12992c4
> > > > > [root@kernelqe3 linux]# git log --oneline -1
> > > > > eeb6b12992c4 (HEAD -> perf-tools-next, perf-tools-next/perf-tools-next) perf jevents: Don't append Unit to desc
> > > > > [root@kernelqe3 linux]# perf test 6 10 'perf all metricgroups test' 'perf all metrics test'
> > > > > 6: Parse event definition strings :
> > > > > 6.1: Test event parsing : Ok
> > > > > 6.2: Parsing of all PMU events from sysfs : FAILED!
> > > > > 6.3: Parsing of given PMU events from sysfs : Ok
> > > > > 6.4: Parsing of aliased events from sysfs : Skip (no aliases in sysfs)
> > > > > 6.5: Parsing of aliased events : FAILED!
> > > > > 6.6: Parsing of terms (event modifiers) : Ok
> > > > > 10: PMU events :
> > > > > 10.1: PMU event table sanity : Ok
> > > > > 10.2: PMU event map aliases : FAILED!
> > > > > 10.3: Parsing of PMU event table metrics : Ok
> > > > > 10.4: Parsing of PMU event table metrics with fake PMUs : FAILED!
> > > > > 10.5: Parsing of metric thresholds with fake PMUs : Ok
> > > > > 93: perf all metricgroups test : FAILED!
> > > > > 94: perf all metrics test : FAILED!
> > > > > [root@kernelqe3 linux]#
> > > > >
> > > > > Bisecting the first problem:
> > > > >
> > > > > 10.2: PMU event map aliases : FAILED!
> > > > >
> > > > > make: Leaving directory '/root/git/linux/tools/perf'
> > > > > 6: Parse event definition strings :
> > > > > 6.1: Test event parsing : Ok
> > > > > 6.2: Parsing of all PMU events from sysfs : Ok
> > > > > 6.3: Parsing of given PMU events from sysfs : Ok
> > > > > 6.4: Parsing of aliased events from sysfs : Skip (no aliases in sysfs)
> > > > > 6.5: Parsing of aliased events : Ok
> > > > > 6.6: Parsing of terms (event modifiers) : Ok
> > > > > 10: PMU events :
> > > > > 10.1: PMU event table sanity : Ok
> > > > > 10.2: PMU event map aliases : FAILED!
> > > > > 10.3: Parsing of PMU event table metrics : Ok
> > > > > 10.4: Parsing of PMU event table metrics with fake PMUs : Ok
> > > > > 10.5: Parsing of metric thresholds with fake PMUs : Ok
> > > > > 93: perf all metricgroups test : Ok
> > > > > 94: perf all metrics test : Ok
> > > > > [root@kernelqe3 linux]# git bisect bad
> > > > > 2e255b4f9f41f137d9e3dc4fae3603a9c2c3dd28 is the first bad commit
> > > > > commit 2e255b4f9f41f137d9e3dc4fae3603a9c2c3dd28
> > > > > Author: Ian Rogers <irogers@xxxxxxxxxx>
> > > > > Date: Wed Aug 23 21:13:16 2023 -0700
> > > > >
> > > > > perf jevents: Group events by PMU
> > > > >
> > > > > Prior to this change a cpuid would map to a list of events where the PMU
> > > > > would be encoded alongside the event information. This change breaks
> > > > > apart each group of events so that there is a group per PMU. A new table
> > > > > is added with the PMU's name and the list of events, the original table
> > > > > now holding an array of these per PMU tables.
> > > > >
> > > > > These changes are to make it easier to get per PMU information about
> > > > > events, rather than the current approach of scanning all events. The
> > > > > perf binary size with BPF skeletons on x86 is reduced by about 1%. The
> > > > > unidentified PMU is now always expanded to "cpu".
> > > > >
> > > > > Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> > > > > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> > > > > Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> > > > > Cc: Gaosheng Cui <cuigaosheng1@xxxxxxxxxx>
> > > > > Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > > > > Cc: James Clark <james.clark@xxxxxxx>
> > > > > Cc: Jing Zhang <renyu.zj@xxxxxxxxxxxxxxxxx>
> > > > > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > > > > Cc: John Garry <john.g.garry@xxxxxxxxxx>
> > > > > Cc: Kajol Jain <kjain@xxxxxxxxxxxxx>
> > > > > Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > > > > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > > > > Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> > > > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > > > > Cc: Ravi Bangoria <ravi.bangoria@xxxxxxx>
> > > > > Cc: Rob Herring <robh@xxxxxxxxxx>
> > > > > Link: https://lore.kernel.org/r/20230824041330.266337-5-irogers@xxxxxxxxxx
> > > > > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > > > >
> > > > > tools/perf/pmu-events/jevents.py | 181 +++++++++++++++++++++++++++++----------
> > > > > tools/perf/tests/pmu-events.c | 30 ++++---
> > > > > 2 files changed, 154 insertions(+), 57 deletions(-)
> > > > > [root@kernelqe3 linux]#
> > > > >
> > > >
> > > > This change defaulted events without a specified PMU to being for the
> > > > PMU 'cpu', so that events in pmu-events.c were associated with a PMU
> > > > and we could find per-PMU information easily. The test events have no
> > > > PMU and so this has broken s390 where the the PMU should be "cpum_cf".
> > > > It has probably also broken x86 hybrid and arm where their default PMU
> > > > isn't cpu. I'll work on a fix, but the problem will be limited to the
> > > > test.
> > >
> > > So, with your "default_core" branche we go to:
> > >
> > > [root@kernelqe3 linux]# perf test 10
> > > 10: PMU events :
> > > 10.1: PMU event table sanity : Ok
> > > 10.2: PMU event map aliases : Ok
> > > 10.3: Parsing of PMU event table metrics : Ok
> > > 10.4: Parsing of PMU event table metrics with fake PMUs : FAILED!
> > > 10.5: Parsing of metric thresholds with fake PMUs : Ok
> > > [root@kernelqe3 linux]# perf --version
> > > perf version 6.5.rc5.g3d63ae82aa12
> > > [root@kernelqe3 linux]#
> > >
> > > The other tests:
> > >
> > > [root@kernelqe3 linux]# perf --version
> > > perf version 6.5.rc5.g3d63ae82aa12
> > > [root@kernelqe3 linux]# perf test 6 10 'perf all metricgroups test' 'perf all metrics test'
> > > 6: Parse event definition strings :
> > > 6.1: Test event parsing : Ok
> > > 6.2: Parsing of all PMU events from sysfs : FAILED!
> > > 6.3: Parsing of given PMU events from sysfs : Ok
> > > 6.4: Parsing of aliased events from sysfs : Skip (no aliases in sysfs)
> > > 6.5: Parsing of aliased events : FAILED!
> > > 6.6: Parsing of terms (event modifiers) : Ok
> > > 10: PMU events :
> > > 10.1: PMU event table sanity : Ok
> > > 10.2: PMU event map aliases : Ok
> > > 10.3: Parsing of PMU event table metrics : Ok
> > > 10.4: Parsing of PMU event table metrics with fake PMUs : FAILED!
> > > 10.5: Parsing of metric thresholds with fake PMUs : Ok
> > > 93: perf all metricgroups test : FAILED!
> > > 94: perf all metrics test : FAILED!
> > > [root@kernelqe3 linux]#
> > >
> > > Trying to bisect it now.
> >
> > make: Leaving directory '/root/git/linux/tools/perf'
> > [root@kernelqe3 linux]# perf test 6
> > 6: Parse event definition strings :
> > 6.1: Test event parsing : Ok
> > 6.2: Parsing of all PMU events from sysfs : FAILED!
> > 6.3: Parsing of given PMU events from sysfs : Ok
> > 6.4: Parsing of aliased events from sysfs : Skip (no aliases in sysfs)
> > 6.5: Parsing of aliased events : FAILED!
> > 6.6: Parsing of terms (event modifiers) : Ok
> > [root@kernelqe3 linux]# git bisect bad
> > 8d4b6d37ea7862d230ad2e1bd4c7d2ff5e9acd53 is the first bad commit
> > commit 8d4b6d37ea7862d230ad2e1bd4c7d2ff5e9acd53
> > Author: Ian Rogers <irogers@xxxxxxxxxx>
> > Date: Wed Aug 23 21:13:28 2023 -0700
> >
> > perf pmu: Lazily load sysfs aliases
> >
> > Don't load sysfs aliases for a PMU when the PMU is first created, defer
> > until an alias needs to be found. For the pmu-scan benchmark, average
> > core PMU scanning is reduced by 30.8%, and average PMU scanning by
> > 12.6%.
> >
> > Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> > Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> > Cc: Gaosheng Cui <cuigaosheng1@xxxxxxxxxx>
> > Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > Cc: James Clark <james.clark@xxxxxxx>
> > Cc: Jing Zhang <renyu.zj@xxxxxxxxxxxxxxxxx>
> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Cc: John Garry <john.g.garry@xxxxxxxxxx>
> > Cc: Kajol Jain <kjain@xxxxxxxxxxxxx>
> > Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Cc: Ravi Bangoria <ravi.bangoria@xxxxxxx>
> > Cc: Rob Herring <robh@xxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20230824041330.266337-17-irogers@xxxxxxxxxx
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> >
> > tools/perf/tests/pmu-events.c | 2 ++
> > tools/perf/util/pmu.c | 81 ++++++++++++++++++++++---------------------
> > tools/perf/util/pmu.h | 2 ++
> > 3 files changed, 46 insertions(+), 39 deletions(-)
> > [root@kernelqe3 linux]#
> >
> > It is segfaulting:
> >
> > 6.2: Parsing of all PMU events from sysfs :
> > --- start ---
> > test child forked, pid 1202947
> > Using CPUID IBM,2964,400,N96,1.4,002f
> > perf: Segmentation fault
> > Obtained 16 stack frames.
> > perf(dump_stack+0x36) [0x1156dbe]
> > perf(sighandler_dump_stack+0x3a) [0x1156e8a]
> > [0x3fffd4790b6]
> > /lib64/libc.so.6(__strcasecmp+0x42) [0x3ffa889c51a]
> > perf() [0x11792ac]
> > perf(pmu_events_table__find_event+0x27c) [0x12432fc]
> > perf() [0x11777cc]
> > perf() [0x1179842]
> > perf(perf_pmu__check_alias+0x4f0) [0x1179e98]
> > perf(parse_events_add_pmu+0x72c) [0x1128e84]
> > perf(parse_events_parse+0x4d4) [0x11754d4]
> > perf(__parse_events+0xda) [0x112644a]
> > perf() [0x10cecb2]
> > perf() [0x10d3264]
> > perf() [0x10cb250]
> > perf(cmd_test+0x109e) [0x10cc756]
> > test child interrupted
> > ---- end ----
> > Parse event definition strings subtest 2: FAILED!
> >
> >
> > Starting program: /root/bin/perf test -F 6
> > [Thread debugging using libthread_db enabled]
> > Using host libthread_db library "/lib64/libthread_db.so.1".
> > 6: Parse event definition strings :
> > 6.1: Test event parsing : Ok
> > 6.2: Parsing of all PMU events from sysfs :
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x000003fffcf1c51a in strcasecmp () from /lib64/libc.so.6
> > #0 0x000003fffcf1c51a in strcasecmp () from /lib64/libc.so.6
> > #1 0x000000000123e518 in assign_str (name=0x1487cc3 "l1i_ondrawer_mem_sourced_writes", field=0x141eeba "value", old_str=0x18c12e0, new_str=0x1487d1f "event=0xb1") at util/pmu.c:449
> > #2 0x000000000123e82c in update_alias (pe=0x3ffffff8ac0, table=0x1555cb0 <pmu_events_map+160>, vdata=0x3ffffff8c40) at util/pmu.c:490
> > #3 0x000000000137b9dc in pmu_events_table.find_event ()
> > #4 0x000000000123ed4e in perf_pmu__new_alias (pmu=0x15ce490, name=0x23c2593 "L1I_ONDRAWER_MEM_SOURCED_WRITES", desc=0x0, val=0x0, val_fd=0x16058a0, pe=0x0) at util/pmu.c:569
> > #5 0x000000000123f370 in pmu_aliases_parse (pmu=0x15ce490) at util/pmu.c:673
> > #6 0x000000000123e3a2 in perf_pmu__find_alias (pmu=0x15ce490, name=0x238eb10 "L1D_OFFDRAWER_SCOL_L3_SOURCED_WRITES_IV", load=true) at util/pmu.c:432
> > #7 0x0000000001241bb2 in pmu_find_alias (pmu=0x15ce490, term=0x18409d0) at util/pmu.c:1439
> > #8 0x0000000001241f82 in perf_pmu__check_alias (pmu=0x15ce490, head_terms=0x21b14d0, info=0x3ffffffa238, err=0x3ffffffc4c8) at util/pmu.c:1519
> > #9 0x00000000011bbbd4 in parse_events_add_pmu (parse_state=0x3ffffffc2f0, list=0x21afec0, name=0x21c6430 "cpum_cf", head_config=0x21b14d0, auto_merge_stats=false, loc_=0x3ffffffb4d8) at util/parse-events.c:1351
> > #10 0x000000000123aa4c in parse_events_parse (_parse_state=0x3ffffffc2f0, scanner=0x15b9310) at util/parse-events.y:299
> > #11 0x00000000011bd190 in parse_events__scanner (str=0x3ffffffc68a "cpum_cf/event=L1D_OFFDRAWER_SCOL_L3_SOURCED_WRITES_IV/u", input=0x0, parse_state=0x3ffffffc2f0) at util/parse-events.c:1738
> > #12 0x00000000011bde00 in __parse_events (evlist=0x15b7030, str=0x3ffffffc68a "cpum_cf/event=L1D_OFFDRAWER_SCOL_L3_SOURCED_WRITES_IV/u", pmu_filter=0x0, err=0x3ffffffc4c8, fake_pmu=0x0, warn_if_reordered=true) at util/parse-events.c:2010
> > #13 0x0000000001121884 in parse_events (evlist=0x15b7030, str=0x3ffffffc68a "cpum_cf/event=L1D_OFFDRAWER_SCOL_L3_SOURCED_WRITES_IV/u", err=0x3ffffffc4c8) at /root/git/linux/tools/perf/util/parse-events.h:40
> > #14 0x0000000001134084 in test_event (e=0x3ffffffc5e0) at tests/parse-events.c:2393
> > #15 0x00000000011349ec in test__pmu_events (test=0x156b860 <suite.parse_events>, subtest=1) at tests/parse-events.c:2551
> > #16 0x000000000111f884 in run_test (test=0x156b860 <suite.parse_events>, subtest=1) at tests/builtin-test.c:242
> > #17 0x000000000111fa1a in test_and_print (t=0x156b860 <suite.parse_events>, subtest=1) at tests/builtin-test.c:271
> > #18 0x00000000011203fa in __cmd_test (argc=1, argv=0x3ffffffe5d0, skiplist=0x0) at tests/builtin-test.c:442
> > #19 0x0000000001120cca in cmd_test (argc=1, argv=0x3ffffffe5d0) at tests/builtin-test.c:564
> > #20 0x00000000011713a4 in run_builtin (p=0x1561190 <commands+600>, argc=3, argv=0x3ffffffe5d0) at perf.c:322
> > #21 0x0000000001171712 in handle_internal_command (argc=3, argv=0x3ffffffe5d0) at perf.c:375
> > #22 0x0000000001171920 in run_argv (argcp=0x3ffffffe304, argv=0x3ffffffe2f8) at perf.c:419
> > #23 0x0000000001171ce8 in main (argc=3, argv=0x3ffffffe5d0) at perf.c:535
> > (gdb)
> >
> > (gdb) fr 1
> > #1 0x000000000123e518 in assign_str (name=0x1487cc3 "l1i_ondrawer_mem_sourced_writes", field=0x141eeba "value", old_str=0x18c12e0, new_str=0x1487d1f "event=0xb1") at util/pmu.c:449
> > 449 if (!new_str || !strcasecmp(*old_str, new_str))
> > (gdb) p new_str
> > $1 = 0x1487d1f "event=0xb1"
> > (gdb) p *old_str
> > $2 = 0x1 <error: Cannot access memory at address 0x1>
> > (gdb) p old_str
> > $3 = (char **) 0x18c12e0
> > (gdb)
>
> I can't explain this, how come the line numbers don't agree with?
> https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/util/pmu.c?h=tmp.perf-tools-next#n449

Probably because this was done in a bisect? I'll redo it with what is in
tmp-perf.tools-next.

> The values are coming from the json event data. I'd need to see the
> generated pmu-events.c.

And provide this file

- Arnaldo