* tip-bot for Stephane Eranian <tipbot@xxxxxxxxx> wrote:
> Commit-ID: 6b89d4c1ae8596a8c9240f169ef108704de373f2
> Gitweb: https://git.kernel.org/tip/6b89d4c1ae8596a8c9240f169ef108704de373f2
> Author: Stephane Eranian <eranian@xxxxxxxxxx>
> AuthorDate: Thu, 9 May 2019 14:45:56 -0700
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> CommitDate: Fri, 10 May 2019 08:04:17 +0200
>
> perf/x86/intel: Fix INTEL_FLAGS_EVENT_CONSTRAINT* masking
>
> On Intel Westmere, a cmdline as follows:
>
> $ perf record -e cpu/event=0xc4,umask=0x2,name=br_inst_retired.near_call/p ....
>
> was failing. Yet the event+ umask support PEBS.
>
> It turns out this is due to a bug in the the PEBS event constraint table for
> westmere. All forms of BR_INST_RETIRED.* support PEBS. Therefore the constraint
> mask should ignore the umask. The name of the macro INTEL_FLAGS_EVENT_CONSTRAINT()
> hint that this is the case but it was not. That macros was checking both the
> event code and event umask. Therefore, it was only matching on 0x00c4.
> There are code+umask macros, they all have *UEVENT*.
>
> This bug fixes the issue by checking only the event code in the mask.
> Both single and range version are modified.
>
> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
> Cc: kan.liang@xxxxxxxxx
> Link: http://lkml.kernel.org/r/20190509214556.123493-1-eranian@xxxxxxxxxx
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> ---
> arch/x86/events/perf_event.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
> index 07fc84bb85c1..a6ac2f4f76fc 100644
> --- a/arch/x86/events/perf_event.h
> +++ b/arch/x86/events/perf_event.h
> @@ -394,10 +394,10 @@ struct cpu_hw_events {
>
> /* Event constraint, but match on all event flags too. */
> #define INTEL_FLAGS_EVENT_CONSTRAINT(c, n) \
> - EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVENT_MASK|X86_ALL_EVENT_FLAGS)
> + EVENT_CONSTRAINT(c, n, ARCH_PERFMON_EVENTSEL_EVENT|X86_ALL_EVENT_FLAGS)
>
> #define INTEL_FLAGS_EVENT_CONSTRAINT_RANGE(c, e, n) \
> - EVENT_CONSTRAINT_RANGE(c, e, n, INTEL_ARCH_EVENT_MASK|X86_ALL_EVENT_FLAGS)
> + EVENT_CONSTRAINT_RANGE(c, e, n, ARCH_PERFMON_EVENTSEL_EVENT|X86_ALL_EVENT_FLAGS)
This commit broke one of my testboxes - and unfortunately I noticed this
too late and the commit is now upstream.
The breakage is that 'perf top' stops working altogether, it errors out
in the event creation:
$ perf top --stdio
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles).
I bisected it back to this commit:
6b89d4c1ae8596a8c9240f169ef108704de373f2 is the first bad commit
commit 6b89d4c1ae8596a8c9240f169ef108704de373f2
Author: Stephane Eranian <eranian@xxxxxxxxxx>
Date: Thu May 9 14:45:56 2019 -0700
perf/x86/intel: Fix INTEL_FLAGS_EVENT_CONSTRAINT* masking
The system is IvyBridge model 62, running a defconfig-ish kernel, and
with perf_event_paranoid set to -1:
[ 3.756600] Performance Events: PEBS fmt1+, IvyBridge events, 16-deep LBR, full-width counters, Intel PMU driver.
processor : 39
vendor_id : GenuineIntel
cpu family : 6
model : 62
model name : Intel(R) Xeon(R) CPU E5-2680 v2 @ 2.80GHz
stepping : 4
microcode : 0x428
If I revert the commit 'perf top' starts working again.
Thanks,
Ingo
|