From: Andi Kleen <ak@linux.intel.com>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, acme@redhat.com,
peterz@infradead.org, mingo@elte.hu, kan.liang@intel.com,
jolsa@redhat.com, namhyung@kernel.org, adrian.hunter@intel.com
Subject: Re: [PATCH 2/3] perf/x86/pebs: add workaround for broken OVFL status on HSW
Date: Thu, 3 Mar 2016 13:43:12 -0800 [thread overview]
Message-ID: <20160303214312.GI23621@tassilo.jf.intel.com> (raw)
In-Reply-To: <1457034642-21837-3-git-send-email-eranian@google.com>
> + /*
> + * There are cases where, even though, the PEBS ovfl bit is set in
> + * GLOBAL_OVF_STATUS, the PEBS events may also have their overflow bits
> + * set for their counters. We must clear them here because they have
> + * been processed as exact samples in the drain_pebs() routine. They
> + * must not be processed again in the for_each_bit_set() loop for
> + * regular samples below.
> + */
> + status &= ~cpuc->pebs_enabled;
> + status &= x86_pmu.intel_ctrl | GLOBAL_STATUS_TRACE_TOPAPMI;
If you just clear the bits here they will not be acked and stay around
forever in GLOBAL_STATUS, which causes other problems.
You need a separate ack_status variable that contains all bits and is always
acked.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2016-03-03 21:43 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-03 19:50 [PATCH 0/3] perf/x86/pebs: various important fixes for PEBS Stephane Eranian
2016-03-03 19:50 ` [PATCH 1/3] perf/x86/intel: add definition for PT PMI bit Stephane Eranian
2016-03-08 13:16 ` [tip:perf/core] perf/x86/intel: Add " tip-bot for Stephane Eranian
2016-03-03 19:50 ` [PATCH 2/3] perf/x86/pebs: add workaround for broken OVFL status on HSW Stephane Eranian
2016-03-03 21:43 ` Andi Kleen [this message]
2016-03-03 23:40 ` Stephane Eranian
2016-03-07 10:24 ` Peter Zijlstra
2016-03-07 12:18 ` Peter Zijlstra
2016-03-07 18:27 ` Jiri Olsa
2016-03-07 20:25 ` Peter Zijlstra
2016-03-08 20:59 ` Stephane Eranian
2016-03-08 21:07 ` Peter Zijlstra
2016-03-08 21:13 ` Stephane Eranian
2016-03-09 5:34 ` Stephane Eranian
2016-03-09 5:44 ` Stephane Eranian
2016-03-09 17:40 ` Stephane Eranian
2016-03-10 10:42 ` Peter Zijlstra
2016-12-14 17:55 ` Peter Zijlstra
2016-12-15 7:26 ` Stephane Eranian
2016-12-15 7:52 ` Jiri Olsa
2016-12-15 8:04 ` Stephane Eranian
2016-12-15 8:42 ` Peter Zijlstra
2016-12-15 16:59 ` Stephane Eranian
2016-12-15 17:10 ` Peter Zijlstra
2016-12-16 8:38 ` Stephane Eranian
2016-12-16 17:48 ` Stephane Eranian
2016-03-10 13:53 ` Peter Zijlstra
2016-03-10 16:10 ` Stephane Eranian
2016-03-08 13:16 ` [tip:perf/core] perf/x86/pebs: Add workaround for broken OVFL status on HSW+ tip-bot for Stephane Eranian
2016-03-03 19:50 ` [PATCH 3/3] perf/x86/pebs: add proper PEBS constraints for Broadwell Stephane Eranian
2016-03-08 13:16 ` [tip:perf/core] perf/x86/pebs: Add " tip-bot for Stephane Eranian
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