Messages in this thread | | | Date | Tue, 21 Nov 2023 15:24:25 +0000 | From | Marc Zyngier <> | Subject | Re: [REGRESSION] Perf (userspace) broken on big.LITTLE systems since v6.5 |
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On Tue, 21 Nov 2023 13:40:31 +0000, Marc Zyngier <maz@kernel.org> wrote: > > [Adding key people on Cc] > > On Tue, 21 Nov 2023 12:08:48 +0000, > Hector Martin <marcan@marcan.st> wrote: > > > > Perf broke on all Apple ARM64 systems (tested almost everything), and > > according to maz also on Juno (so, probably all big.LITTLE) since v6.5. > > I can confirm that at least on 6.7-rc2, perf is pretty busted on any > asymmetric ARM platform. It isn't clear what criteria is used to pick > the PMU, but nothing works anymore. > > The saving grace in my case is that Debian still ships a 6.1 perftool > package, but that's obviously not going to last. > > I'm happy to test potential fixes.
At Mark's request, I've dumped a couple of perf (as of -rc2) runs with -vvv. And it is quite entertaining (this is taskset to an 'icestorm' CPU):
<quote> maz@valley-girl:~/hot-poop/arm-platforms/tools/perf$ sudo taskset -c 0 ./perf stat -vvv -e apple_icestorm_pmu/cycles/ -e apple_firestorm_pmu/cycles/ -e cycles ls Using CPUID 0x00000000612f0280 Attempt to add: apple_icestorm_pmu/cycles=0/ ..after resolving event: apple_icestorm_pmu/cycles=0/ Opening: unknown-hardware:HG ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0xb00000000 disabled 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 sys_perf_event_open failed, error -95 Attempt to add: apple_firestorm_pmu/cycles=0/ ..after resolving event: apple_firestorm_pmu/cycles=0/ Control descriptor is not initialized Opening: apple_icestorm_pmu/cycles/ ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 1045843 cpu -1 group_fd -1 flags 0x8 = 3 Opening: apple_firestorm_pmu/cycles/ ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 1045843 cpu -1 group_fd -1 flags 0x8 = 4 Opening: cycles ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 1045843 cpu -1 group_fd -1 flags 0x8 = 5 arch builtin-diff.o builtin-mem.o common-cmds.h perf-completion.sh bench builtin-evlist.c builtin-probe.c CREDITS perf.h Build builtin-evlist.o builtin-probe.o design.txt perf-in.o builtin-annotate.c builtin-ftrace.c builtin-record.c dlfilters perf-iostat builtin-annotate.o builtin-ftrace.o builtin-record.o Documentation perf-iostat.sh builtin-bench.c builtin.h builtin-report.c FEATURE-DUMP perf.o builtin-bench.o builtin-help.c builtin-report.o include perf-read-vdso.c builtin-buildid-cache.c builtin-help.o builtin-sched.c jvmti perf-sys.h builtin-buildid-cache.o builtin-inject.c builtin-script.c libapi PERF-VERSION-FILE builtin-buildid-list.c builtin-inject.o builtin-script.o libperf perf-with-kcore builtin-buildid-list.o builtin-kallsyms.c builtin-stat.c libsubcmd pmu-events builtin-c2c.c builtin-kallsyms.o builtin-stat.o libsymbol python builtin-c2c.o builtin-kmem.c builtin-timechart.c Makefile python_ext_build builtin-config.c builtin-kvm.c builtin-top.c Makefile.config scripts builtin-config.o builtin-kvm.o builtin-top.o Makefile.perf tests builtin-daemon.c builtin-kwork.c builtin-trace.c MANIFEST trace builtin-daemon.o builtin-list.c builtin-version.c perf ui builtin-data.c builtin-list.o builtin-version.o perf-archive util builtin-data.o builtin-lock.c check-headers.sh perf-archive.sh builtin-diff.c builtin-mem.c command-list.txt perf.c apple_icestorm_pmu/cycles/: -1: 0 873709 0 apple_firestorm_pmu/cycles/: -1: 0 873709 0 cycles: -1: 0 873709 0 apple_icestorm_pmu/cycles/: 0 873709 0 apple_firestorm_pmu/cycles/: 0 873709 0 cycles: 0 873709 0
Performance counter stats for 'ls':
<not counted> apple_icestorm_pmu/cycles/ (0.00%) <not counted> apple_firestorm_pmu/cycles/ (0.00%) <not counted> cycles (0.00%)
0.000002250 seconds time elapsed
0.000000000 seconds user 0.000000000 seconds sys </quote>
If I run the same thing on another CPU cluster (firestorm), I get this:
<quote> maz@valley-girl:~/hot-poop/arm-platforms/tools/perf$ sudo taskset -c 2 ./perf stat -vvv -e apple_icestorm_pmu/cycles/ -e apple_firestorm_pmu/cycles/ -e cycles ls Using CPUID 0x00000000612f0280 Attempt to add: apple_icestorm_pmu/cycles=0/ ..after resolving event: apple_icestorm_pmu/cycles=0/ Opening: unknown-hardware:HG ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0xb00000000 disabled 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 sys_perf_event_open failed, error -95 Attempt to add: apple_firestorm_pmu/cycles=0/ ..after resolving event: apple_firestorm_pmu/cycles=0/ Control descriptor is not initialized Opening: apple_icestorm_pmu/cycles/ ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 1045925 cpu -1 group_fd -1 flags 0x8 = 3 Opening: apple_firestorm_pmu/cycles/ ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 1045925 cpu -1 group_fd -1 flags 0x8 = 4 Opening: cycles ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 1045925 cpu -1 group_fd -1 flags 0x8 = 5 arch builtin-diff.o builtin-mem.o common-cmds.h perf-completion.sh bench builtin-evlist.c builtin-probe.c CREDITS perf.h Build builtin-evlist.o builtin-probe.o design.txt perf-in.o builtin-annotate.c builtin-ftrace.c builtin-record.c dlfilters perf-iostat builtin-annotate.o builtin-ftrace.o builtin-record.o Documentation perf-iostat.sh builtin-bench.c builtin.h builtin-report.c FEATURE-DUMP perf.o builtin-bench.o builtin-help.c builtin-report.o include perf-read-vdso.c builtin-buildid-cache.c builtin-help.o builtin-sched.c jvmti perf-sys.h builtin-buildid-cache.o builtin-inject.c builtin-script.c libapi PERF-VERSION-FILE builtin-buildid-list.c builtin-inject.o builtin-script.o libperf perf-with-kcore builtin-buildid-list.o builtin-kallsyms.c builtin-stat.c libsubcmd pmu-events builtin-c2c.c builtin-kallsyms.o builtin-stat.o libsymbol python builtin-c2c.o builtin-kmem.c builtin-timechart.c Makefile python_ext_build builtin-config.c builtin-kvm.c builtin-top.c Makefile.config scripts builtin-config.o builtin-kvm.o builtin-top.o Makefile.perf tests builtin-daemon.c builtin-kwork.c builtin-trace.c MANIFEST trace builtin-daemon.o builtin-list.c builtin-version.c perf ui builtin-data.c builtin-list.o builtin-version.o perf-archive util builtin-data.o builtin-lock.c check-headers.sh perf-archive.sh builtin-diff.c builtin-mem.c command-list.txt perf.c apple_icestorm_pmu/cycles/: -1: 1035101 469125 469125 apple_firestorm_pmu/cycles/: -1: 1035035 469125 469125 cycles: -1: 1034653 469125 469125 apple_icestorm_pmu/cycles/: 1035101 469125 469125 apple_firestorm_pmu/cycles/: 1035035 469125 469125 cycles: 1034653 469125 469125
Performance counter stats for 'ls':
1,035,101 apple_icestorm_pmu/cycles/ 1,035,035 apple_firestorm_pmu/cycles/ 1,034,653 cycles
0.000001333 seconds time elapsed
0.000000000 seconds user 0.000000000 seconds sys </quote>
which doesn't make any sense either. I really don't understand what this PERF_TYPE_HARDWARE does here (the *real* types are 10 and 11), nor what this 'cycle=0' stuff is.
/puzzled
M.
-- Without deviation from the norm, progress is not possible.
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