From: Robert Richter <robert.richter@amd.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>,
Stephane Eranian <eranian@google.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Robert Richter <robert.richter@amd.com>
Subject: [PATCH 04/12] perf/x86-ibs: Fix frequency profiling
Date: Mon, 2 Apr 2012 20:19:10 +0200 [thread overview]
Message-ID: <1333390758-10893-5-git-send-email-robert.richter@amd.com> (raw)
In-Reply-To: <1333390758-10893-1-git-send-email-robert.richter@amd.com>
Fixing profiling at a fix frequency, in this case the freq value and
sample period was setup incorrectly. Since sampling periods are
adjusted we also allow periods that have lower 4 bits set.
Another fix is the setup of the hw counter: If we modify
hwc->sample_period, we also need to update hwc->last_period and
hwc->period_left.
Signed-off-by: Robert Richter <robert.richter@amd.com>
---
arch/x86/kernel/cpu/perf_event_amd_ibs.c | 18 ++++++++++++++++--
1 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
index 6f00ee3..eec3ea2 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -162,9 +162,16 @@ static int perf_ibs_init(struct perf_event *event)
if (config & perf_ibs->cnt_mask)
/* raw max_cnt may not be set */
return -EINVAL;
- if (hwc->sample_period & 0x0f)
- /* lower 4 bits can not be set in ibs max cnt */
+ if (!event->attr.sample_freq && hwc->sample_period & 0x0f)
+ /*
+ * lower 4 bits can not be set in ibs max cnt,
+ * but allowing it in case we adjust the
+ * sample period to set a frequency.
+ */
return -EINVAL;
+ hwc->sample_period &= ~0x0FULL;
+ if (!hwc->sample_period)
+ hwc->sample_period = 0x10;
} else {
max_cnt = config & perf_ibs->cnt_mask;
config &= ~perf_ibs->cnt_mask;
@@ -175,6 +182,13 @@ static int perf_ibs_init(struct perf_event *event)
if (!hwc->sample_period)
return -EINVAL;
+ /*
+ * If we modify hwc->sample_period, we also need to update
+ * hwc->last_period and hwc->period_left.
+ */
+ hwc->last_period = hwc->sample_period;
+ local64_set(&hwc->period_left, hwc->sample_period);
+
hwc->config_base = perf_ibs->msr;
hwc->config = config;
--
1.7.8.4
next prev parent reply other threads:[~2012-04-02 18:22 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-02 18:19 [PATCH 00/12] perf/x86-ibs: Precise event sampling with IBS for AMD CPUs Robert Richter
2012-04-02 18:19 ` [PATCH 01/12] perf/x86-ibs: Fix update of period Robert Richter
2012-05-09 14:29 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 02/12] perf: Pass last sampling period to perf_sample_data_init() Robert Richter
2012-05-09 14:30 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 03/12] perf/x86-ibs: Enable ibs op micro-ops counting mode Robert Richter
2012-05-09 14:31 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` Robert Richter [this message]
2012-05-09 14:32 ` [tip:perf/core] perf/x86-ibs: Fix frequency profiling tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 05/12] perf/x86-ibs: Take instruction pointer from ibs sample Robert Richter
2012-05-09 14:33 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 06/12] perf/x86-ibs: Precise event sampling with IBS for AMD CPUs Robert Richter
2012-04-14 10:21 ` Peter Zijlstra
2012-04-23 9:56 ` Robert Richter
2012-04-27 12:34 ` Robert Richter
2012-04-27 12:39 ` Stephane Eranian
2012-04-27 12:54 ` Robert Richter
2012-04-27 13:10 ` Stephane Eranian
2012-04-27 15:18 ` Robert Richter
2012-04-27 15:30 ` Peter Zijlstra
2012-04-27 15:57 ` Stephane Eranian
2012-04-27 15:30 ` Peter Zijlstra
2012-04-27 16:09 ` Robert Richter
2012-04-27 16:21 ` Peter Zijlstra
2012-04-27 16:23 ` Stephane Eranian
2012-04-14 10:22 ` Peter Zijlstra
2012-04-23 8:41 ` Robert Richter
2012-04-23 10:36 ` Peter Zijlstra
2012-04-14 10:24 ` Peter Zijlstra
2012-04-23 10:08 ` Robert Richter
2012-05-02 10:33 ` [PATCH v2] " Robert Richter
2012-05-02 11:14 ` Peter Zijlstra
2012-05-04 17:53 ` Peter Zijlstra
2012-05-09 14:34 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 07/12] perf/x86-ibs: Rename some variables Robert Richter
2012-05-09 14:34 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 08/12] perf/x86-ibs: Trigger overflow if remaining period is too small Robert Richter
2012-05-09 14:35 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 09/12] perf/x86-ibs: Extend hw period that triggers overflow Robert Richter
2012-05-09 14:36 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 10/12] perf/x86-ibs: Implement workaround for IBS erratum #420 Robert Richter
2012-05-09 14:37 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 11/12] perf/x86-ibs: Catch spurious interrupts after stopping ibs Robert Richter
2012-05-09 14:38 ` [tip:perf/core] perf/x86-ibs: Catch spurious interrupts after stopping IBS tip-bot for Robert Richter
2012-04-02 18:19 ` [PATCH 12/12] perf/x86-ibs: Fix usage of IBS op current count Robert Richter
2012-05-09 14:39 ` [tip:perf/core] " tip-bot for Robert Richter
2012-04-02 19:11 ` [PATCH 00/12] perf/x86-ibs: Precise event sampling with IBS for AMD CPUs Ingo Molnar
2012-04-03 10:48 ` Robert Richter
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