Messages in this thread | | | Date | Tue, 21 Nov 2023 16:02:55 +0000 | From | Mark Rutland <> | Subject | Re: [REGRESSION] Perf (userspace) broken on big.LITTLE systems since v6.5 |
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On Tue, Nov 21, 2023 at 07:46:57AM -0800, Ian Rogers wrote: > On Tue, Nov 21, 2023 at 7:40 AM Mark Rutland <mark.rutland@arm.com> wrote: > > > > On Tue, Nov 21, 2023 at 03:24:25PM +0000, Marc Zyngier wrote: > > > 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): > > > > IIUC the tool is doing the wrong thing here and overriding explicit > > ${pmu}/${event}/ events with PERF_TYPE_HARDWARE events rather than events using > > that ${pmu}'s type and event namespace. > > > > Regardless of the *new* ABI that allows PERF_TYPE_HARDWARE events to be > > targetted to a specific PMU, it's semantically wrong to rewrite events like > > this since ${pmu}/${event}/ is not necessarily equivalent to a similarly-named > > PERF_COUNT_HW_${EVENT}. > > If you name a PMU and an event then the event should only be opened on > that PMU, 100% agree. There's a bunch of output, but when the legacy > cycles event is opened it appears to be because it was explicitly > requested.
I think you've missed that the named PMU events are being erreously transformed into PERF_TYPE_HARDWARE events. Look at the -vvv output, e.g.
Opening: apple_firestorm_pmu/cycles/ ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) size 136 config 0 (PERF_COUNT_HW_CPU_CYCLES) sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 inherit 1 enable_on_exec 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid 1045843 cpu -1 group_fd -1 flags 0x8 = 4
... which should not be PERF_TYPE_HARDWARE && PERF_COUNT_HW_CPU_CYCLES.
Marc said that he bisected the issue down to commit:
5ea8f2ccffb23983 ("perf parse-events: Support hardware events as terms")
... so it looks like something is going wrong when the events are being parsed, e.g. losing the HW PMU information?
Thanks, Mark.
> > > Thanks, > Ian > > > Mark. > > > > > <quote> > > > maz@valley-girl:~/hot-poop/arm-platforms/tools/perf$ 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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