Re: perf test hybrid failing on 14700K

From: Ian Rogers
Date: Wed Jan 03 2024 - 11:31:54 EST


On Wed, Jan 3, 2024 at 6:16 AM Liang, Kan <kan.liang@xxxxxxxxxxxxxxx> wrote:
>
>
>
> On 2024-01-02 5:41 p.m., Ian Rogers wrote:
> > On Tue, Jan 2, 2024 at 7:43 AM Liang, Kan <kan.liang@xxxxxxxxxxxxxxx> wrote:
> >>
> >>
> >>
> >> On 2023-12-23 8:55 a.m., Arnaldo Carvalho de Melo wrote:
> >>> Hi Kan,
> >>>
> >>> I noticed the following problem, are you able to reproduce it?
> >>>
> >>> Happy solstice!
> >>
> >> Happy new year!
> >>
> >>>
> >>> - Arnaldo
> >>>
> >>> root@number:/home/acme/Downloads# grep "model name" -m1 /proc/cpuinfo
> >>> model name : Intel(R) Core(TM) i7-14700K
> >>> root@number:/home/acme/Downloads# uname -a
> >>> Linux number 6.6.4-200.fc39.x86_64 #1 SMP PREEMPT_DYNAMIC Sun Dec 3 18:13:11 UTC 2023 x86_64 GNU/Linux
> >>> root@number:/home/acme/Downloads# perf -vv
> >>> perf version 6.7.rc6.g63daba4e2861
> >>> dwarf: [ on ] # HAVE_DWARF_SUPPORT
> >>> dwarf_getlocations: [ on ] # HAVE_DWARF_GETLOCATIONS_SUPPORT
> >>> syscall_table: [ on ] # HAVE_SYSCALL_TABLE_SUPPORT
> >>> libbfd: [ OFF ] # HAVE_LIBBFD_SUPPORT
> >>> debuginfod: [ on ] # HAVE_DEBUGINFOD_SUPPORT
> >>> libelf: [ on ] # HAVE_LIBELF_SUPPORT
> >>> libnuma: [ on ] # HAVE_LIBNUMA_SUPPORT
> >>> numa_num_possible_cpus: [ on ] # HAVE_LIBNUMA_SUPPORT
> >>> libperl: [ on ] # HAVE_LIBPERL_SUPPORT
> >>> libpython: [ on ] # HAVE_LIBPYTHON_SUPPORT
> >>> libslang: [ on ] # HAVE_SLANG_SUPPORT
> >>> libcrypto: [ on ] # HAVE_LIBCRYPTO_SUPPORT
> >>> libunwind: [ on ] # HAVE_LIBUNWIND_SUPPORT
> >>> libdw-dwarf-unwind: [ on ] # HAVE_DWARF_SUPPORT
> >>> zlib: [ on ] # HAVE_ZLIB_SUPPORT
> >>> lzma: [ on ] # HAVE_LZMA_SUPPORT
> >>> get_cpuid: [ on ] # HAVE_AUXTRACE_SUPPORT
> >>> bpf: [ on ] # HAVE_LIBBPF_SUPPORT
> >>> aio: [ on ] # HAVE_AIO_SUPPORT
> >>> zstd: [ on ] # HAVE_ZSTD_SUPPORT
> >>> libpfm4: [ on ] # HAVE_LIBPFM
> >>> libtraceevent: [ on ] # HAVE_LIBTRACEEVENT
> >>> bpf_skeletons: [ on ] # HAVE_BPF_SKEL
> >>> root@number:/home/acme/Downloads# perf test 75
> >>> 75: x86 hybrid : FAILED!
> >>
> >> The failure should be a regression caused by the a24d9d9dc096 ("perf
> >> parse-events: Make legacy events lower priority than sysfs/JSON")
> >>
> >> @@ -1004,10 +1012,19 @@ static int config_term_pmu(struct
> >> perf_event_attr *attr,
> >> err_str, /*help=*/NULL);
> >> return -EINVAL;
> >> }
> >> - attr->type = PERF_TYPE_HARDWARE;
> >> - attr->config = term->val.num;
> >> - if (perf_pmus__supports_extended_type())
> >> - attr->config |= (__u64)pmu->type << PERF_PMU_TYPE_SHIFT;
> >> + /*
> >> + * If the PMU has a sysfs or json event prefer it over
> >> + * legacy. ARM requires this.
> >> + */
> >> + if (perf_pmu__have_event(pmu, term->config))
> >> For Intel hybrid, the perf_pmu__have_event() should be always true for
> >> all hw events and hw cache events. So the patch will mistakenly update
> >> the type to TYPE_USER. However, On Intel platforms, the type of the hw
> >> events should be TYPE_HARDWARE.
> >>
> >> Seems ARM needs to find another way to distinguish the case.
> >>
> >> Ian, any suggestions?
> >
> > Hi Kan/Mark,
> >
> > Firstly, the perf_pmu__have_event is a test of whether
> > /sys/devices/<pmu>/events or the equivalent json events have the
> > specified event string like "inst_retired.any" - ie it isn't a test of
> > whether the event is supported by the kernel. Mark was quite insistent
> > that the behavior be changed so that if a legacy event is specified
> > with a PMU, the PMU's sysfs/json event is the priority which is a big
> > behavior change on x86.
> >
> > To get the test passing again I've sent out a test update:
> > https://lore.kernel.org/lkml/20240102215732.1125997-1-irogers@xxxxxxxxxx/
> > This switches the legacy events in the test to ones which don't have
> > sysfs or json equivalents. The test is somewhat brittle as an x86 PMU
> > change could decide to add /sys/devices/cpu/events/cycles alongside
> > /sys/devices/cpu/events/cpu-cycles.
>
> I think the cycles, cpu-cycles, and instructions are treated as
> architectural events in both Linux and X86. I don't think there is a
> plan to change the behavior of the architectural events.
>
> > Ideally we'd be testing all events
> > on core PMUs, for legacy events they may have a sysfs/json override
> > and the test expectation should expect this and assert that the type
> > isn't PERF_TYPE_HARDWARE, etc. For now what I sent out is sufficient
> > to get the "x86 hybrid" test passing.
>
> Before the a24d9d9dc096, the "cpu-cycles" and the "cycles" are
> identical. It should be fine to verify either of them.
>
> But after the a24d9d9dc096, the code path is different.

It isn't so much that the code path is different, after a24d9d9dc096
we prefer events defined in sysfs/json over legacy events, as that
exists for "cpu-cycles" then we get the test failures. Using "cycles"
is a fix purely because /sys/devices/cpu_core/events/cycles doesn't
exist, but this is somewhat arbitrary.

> So maybe it's
> better to verify both of the "cpu-cycles" and the "cycles" in the x86
> hybrid test. Adding a new case something as below should be enough.
>
> {
> .name = "{cpu_core/cpu-cycles/,cpu_core/cycles/}",
> .check = test__hybrid_hw_group_2_event,
> },
>
> Thanks,
> Kan

More tests is a good thing, I'll add that in v2 along with the Reported-by.

Thanks,
Ian

> > I should probably have done the
> > whole Reported-by.. thing, sorry for missing that.
> >
> > Thanks,
> > Ian
> >
> >>
> >> + term->type_term = PARSE_EVENTS__TERM_TYPE_USER;
> >> + term->no_value = true;
> >> + } else {
> >> + attr->type = PERF_TYPE_HARDWARE;
> >> + attr->config = term->val.num;
> >> + if (perf_pmus__supports_extended_type())
> >> + attr->config |= (__u64)pmu->type << PERF_PMU_TYPE_SHIFT;
> >> + }
> >> return 0;
> >> }
> >> if (term->type_term == PARSE_EVENTS__TERM_TYPE_USER ||
> >>
> >>
> >> Thanks,
> >> Kan
> >>> root@number:/home/acme/Downloads# perf test -v 75
> >>> 75: x86 hybrid :
> >>> --- start ---
> >>> test child forked, pid 4111587
> >>> Using CPUID GenuineIntel-6-B7-1
> >>> running test 0 'cpu_core/cpu-cycles/'
> >>> FAILED arch/x86/tests/hybrid.c:30 wrong type
> >>> Event test failure: test 0 'cpu_core/cpu-cycles/'running test 1 '{cpu_core/cpu-cycles/,cpu_core/instructions/}'
> >>> FAILED arch/x86/tests/hybrid.c:42 wrong type
> >>> Event test failure: test 1 '{cpu_core/cpu-cycles/,cpu_core/instructions/}'running test 2 '{cpu-clock,cpu_core/cpu-cycles/}'
> >>> FAILED arch/x86/tests/hybrid.c:65 wrong type
> >>> Event test failure: test 2 '{cpu-clock,cpu_core/cpu-cycles/}'running test 3 '{cpu_core/cpu-cycles/,cpu-clock}'
> >>> FAILED arch/x86/tests/hybrid.c:78 wrong type
> >>> Event test failure: test 3 '{cpu_core/cpu-cycles/,cpu-clock}'running test 4 '{cpu_core/cpu-cycles/k,cpu_core/instructions/u}'
> >>> FAILED arch/x86/tests/hybrid.c:95 wrong type
> >>> Event test failure: test 4 '{cpu_core/cpu-cycles/k,cpu_core/instructions/u}'running test 5 'r1a'
> >>> running test 6 'cpu_core/r1a/'
> >>> running test 7 'cpu_core/config=10,config1,config2=3,period=1000/u'
> >>> WARNING: event 'N/A' not valid (bits 0-1 of config2 '3' not supported by kernel)!
> >>> running test 8 'cpu_core/LLC-loads/'
> >>> test child finished with -1
> >>> ---- end ----
> >>> x86 hybrid: FAILED!
> >>> root@number:/home/acme/Downloads#
> >>>
> >>> root@number:/home/acme/Downloads# perf trace -e perf_event_open perf test -F -v 75
> >>> 75: x86 hybrid :
> >>> --- start ---
> >>> Using CPUID GenuineIntel-6-B7-1
> >>> running test 0 'cpu_core/cpu-cycles/'
> >>> FAILED arch/x86/tests/hybrid.c:30 wrong type
> >>> Event test failure: test 0 'cpu_core/cpu-cycles/'running test 1 '{cpu_core/cpu-cycles/,cpu_core/instructions/}'
> >>> FAILED arch/x86/tests/hybrid.c:42 wrong type
> >>> Event test failure: test 1 '{cpu_core/cpu-cycles/,cpu_core/instructions/}'running test 2 '{cpu-clock,cpu_core/cpu-cycles/}'
> >>> FAILED arch/x86/tests/hybrid.c:65 wrong type
> >>> Event test failure: test 2 '{cpu-clock,cpu_core/cpu-cycles/}'running test 3 '{cpu_core/cpu-cycles/,cpu-clock}'
> >>> FAILED arch/x86/tests/hybrid.c:78 wrong type
> >>> Event test failure: test 3 '{cpu_core/cpu-cycles/,cpu-clock}'running test 4 '{cpu_core/cpu-cycles/k,cpu_core/instructions/u}'
> >>> FAILED arch/x86/tests/hybrid.c:95 wrong type
> >>> Event test failure: test 4 '{cpu_core/cpu-cycles/k,cpu_core/instructions/u}'running test 5 'r1a'
> >>> running test 6 'cpu_core/r1a/'
> >>> running test 7 'cpu_core/config=10,config1,config2=3,period=1000/u'
> >>> WARNING: event 'N/A' not valid (bits 0-1 of config2 '3' not supported by kernel)!
> >>> running test 8 'cpu_core/LLC-loads/'
> >>> ---- end ----
> >>> x86 hybrid: FAILED!
> >>> 0.000 ( 0.008 ms): :4115165/4115165 perf_event_open(attr_uptr: { type: 0 (PERF_TYPE_HARDWARE), config: 0xa00000000, disabled: 1, { bp_len, config2 }: 0x900000000, branch_sample_type: USER|COUNTERS, sample_regs_user: 0x3ecaddffffffff, sample_stack_user: 4115165, clockid: 925535355, sample_regs_intr: 0x8140c90000a8f7, sample_max_stack: 8, sig_data: 120259084288 }, cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 3
> >>> 0.010 ( 0.002 ms): :4115165/4115165 perf_event_open(attr_uptr: { type: 0 (PERF_TYPE_HARDWARE), config: 0x400000000, disabled: 1, { bp_len, config2 }: 0x900000000, branch_sample_type: USER|COUNTERS, sample_regs_user: 0x3ecaddffffffff, sample_stack_user: 4115165, clockid: 925538919, sample_regs_intr: 0x8140c90000a8f7, sample_max_stack: 8, sig_data: 120259084288 }, cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
> >>> root@number:/home/acme/Downloads# strace -e perf_event_open perf test -F -v 75
> >>> 75: x86 hybrid :
> >>> --- start ---
> >>> Using CPUID GenuineIntel-6-B7-1
> >>> running test 0 'cpu_core/cpu-cycles/'
> >>> FAILED arch/x86/tests/hybrid.c:30 wrong type
> >>> Event test failure: test 0 'cpu_core/cpu-cycles/'running test 1 '{cpu_core/cpu-cycles/,cpu_core/instructions/}'
> >>> FAILED arch/x86/tests/hybrid.c:42 wrong type
> >>> Event test failure: test 1 '{cpu_core/cpu-cycles/,cpu_core/instructions/}'running test 2 '{cpu-clock,cpu_core/cpu-cycles/}'
> >>> FAILED arch/x86/tests/hybrid.c:65 wrong type
> >>> Event test failure: test 2 '{cpu-clock,cpu_core/cpu-cycles/}'running test 3 '{cpu_core/cpu-cycles/,cpu-clock}'
> >>> FAILED arch/x86/tests/hybrid.c:78 wrong type
> >>> Event test failure: test 3 '{cpu_core/cpu-cycles/,cpu-clock}'running test 4 '{cpu_core/cpu-cycles/k,cpu_core/instructions/u}'
> >>> FAILED arch/x86/tests/hybrid.c:95 wrong type
> >>> Event test failure: test 4 '{cpu_core/cpu-cycles/k,cpu_core/instructions/u}'running test 5 'r1a'
> >>> running test 6 'cpu_core/r1a/'
> >>> running test 7 'cpu_core/config=10,config1,config2=3,period=1000/u'
> >>> WARNING: event 'N/A' not valid (bits 0-1 of config2 '3' not supported by kernel)!
> >>> running test 8 'cpu_core/LLC-loads/'
> >>> perf_event_open({type=PERF_TYPE_HARDWARE, size=0 /* PERF_ATTR_SIZE_??? */, config=0xa<<32|PERF_COUNT_HW_CPU_CYCLES, sample_period=0, sample_type=0, read_format=0, disabled=1, precise_ip=0 /* arbitrary skid */, ...}, 0, -1, -1, PERF_FLAG_FD_CLOEXEC) = 3
> >>> perf_event_open({type=PERF_TYPE_HARDWARE, size=0 /* PERF_ATTR_SIZE_??? */, config=0x4<<32|PERF_COUNT_HW_CPU_CYCLES, sample_period=0, sample_type=0, read_format=0, disabled=1, precise_ip=0 /* arbitrary skid */, ...}, 0, -1, -1, PERF_FLAG_FD_CLOEXEC) = 4
> >>> ---- end ----
> >>> x86 hybrid: FAILED!
> >>> +++ exited with 0 +++
> >>> root@number:/home/acme/Downloads#
> >>>
> >