From: Peter Zijlstra <peterz@infradead.org>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Stephane Eranian <eranian@google.com>,
Vince Weaver <vincent.weaver@maine.edu>,
Ingo Molnar <mingo@kernel.org>,
David Carrillo-Cisneros <davidcc@google.com>,
"H. Peter Anvin" <hpa@zytor.com>, Kan Liang <kan.liang@intel.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Paul Turner <pjt@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
linux-tip-commits@vger.kernel.org
Subject: Re: [tip:perf/core] perf/core: Check return value of the perf_event_read() IPI
Date: Tue, 30 Aug 2016 08:47:24 +0200 [thread overview]
Message-ID: <20160830064724.GX10153@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160829185841.GA27077@krava>
On Mon, Aug 29, 2016 at 08:58:41PM +0200, Jiri Olsa wrote:
> couldn't we just call smp_call_function_single(cpu_to_read, __perf_event_read, ...
> once we read oncpu != -1 ?
>
Yes, and at that point we can simply revert this WARN, because that is
exactly the same.
Which I think is what I'm going to do.
If oncpu is not valid, the sched_out that made it invalid will have
updated the event count and we're good.
All I'll leave is an explicit comment that we've ignored the
smp_call_function_single() return value on purpose.
next prev parent reply other threads:[~2016-08-30 6:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 20:55 [PATCH v3 0/4] remove unnecessary IPI reading uncore events David Carrillo-Cisneros
2016-08-17 20:55 ` [PATCH v3 1/4] perf/core: check return value of perf_event_read IPI David Carrillo-Cisneros
2016-08-18 10:52 ` [tip:perf/core] perf/core: Check return value of the perf_event_read() IPI tip-bot for David Carrillo-Cisneros
2016-08-21 12:10 ` Vegard Nossum
2016-08-22 7:17 ` Jiri Olsa
2016-08-22 8:29 ` Jiri Olsa
2016-08-22 10:38 ` Jiri Olsa
2016-08-28 18:09 ` Jiri Olsa
2016-08-29 10:03 ` Peter Zijlstra
2016-08-29 13:02 ` Peter Zijlstra
2016-08-29 13:14 ` Vince Weaver
2016-08-29 18:58 ` Jiri Olsa
2016-08-30 6:47 ` Peter Zijlstra [this message]
2016-08-30 7:26 ` Peter Zijlstra
2016-08-30 9:47 ` Jiri Olsa
2016-08-30 16:26 ` Stephane Eranian
2016-09-02 8:33 ` Peter Zijlstra
2016-10-09 7:09 ` [lkp] [perf/core] 412929295f: WARNING: CPU: 2 PID: 600 at kernel/events/core.c:3530 perf_event_read+0x17d/0x190 kernel test robot
2016-08-17 20:55 ` [PATCH v3 2/4] perf/core: generalize event->group_flags David Carrillo-Cisneros
2016-08-18 10:53 ` [tip:perf/core] perf/core: Generalize event->group_flags tip-bot for David Carrillo-Cisneros
2016-08-17 20:55 ` [PATCH v3 3/4] perf/core: introduce PMU_EV_CAP_READ_ACTIVE_PKG David Carrillo-Cisneros
2016-08-18 10:54 ` [tip:perf/core] perf/core: Introduce PMU_EV_CAP_READ_ACTIVE_PKG tip-bot for David Carrillo-Cisneros
2016-08-17 20:55 ` [PATCH v3 4/4] perf/x86: use PMUEF_READ_CPU_PKG in uncore events David Carrillo-Cisneros
2016-08-18 10:54 ` [tip:perf/core] perf/x86: Use " tip-bot for David Carrillo-Cisneros
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