From: kan.liang@linux.intel.com
To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org
Cc: acme@kernel.org, ak@linux.intel.com, mark.rutland@arm.com,
luto@amacapital.net, eranian@google.com, namhyung@kernel.org,
Kan Liang <kan.liang@linux.intel.com>
Subject: [PATCH V3 1/2] perf/x86: Move cpuc->running into P4 specific code
Date: Tue, 13 Apr 2021 11:57:29 -0700 [thread overview]
Message-ID: <1618340250-29027-1-git-send-email-kan.liang@linux.intel.com> (raw)
From: Kan Liang <kan.liang@linux.intel.com>
The 'running' variable is only used in the P4 PMU. Current perf sets the
variable in the critical function x86_pmu_start(), which wastes cycles
for everybody not running on P4.
Move cpuc->running into the P4 specific p4_pmu_enable_event().
Add a static per-CPU 'p4_running' variable to replace the 'running'
variable in the struct cpu_hw_events. Saves space for the generic
structure.
The p4_pmu_enable_all() also invokes the p4_pmu_enable_event(), but it
should not set cpuc->running. Factor out __p4_pmu_enable_event() for
p4_pmu_enable_all().
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
New patch for V3
- Address the suggestion from Peter.
https://lore.kernel.org/lkml/20200908155840.GC35926@hirez.programming.kicks-ass.net/
arch/x86/events/core.c | 1 -
arch/x86/events/intel/p4.c | 16 +++++++++++++---
arch/x86/events/perf_event.h | 1 -
3 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 18df171..dd9f3c2 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1480,7 +1480,6 @@ static void x86_pmu_start(struct perf_event *event, int flags)
cpuc->events[idx] = event;
__set_bit(idx, cpuc->active_mask);
- __set_bit(idx, cpuc->running);
static_call(x86_pmu_enable)(event);
perf_event_update_userpage(event);
}
diff --git a/arch/x86/events/intel/p4.c b/arch/x86/events/intel/p4.c
index a4cc660..9c10cbb 100644
--- a/arch/x86/events/intel/p4.c
+++ b/arch/x86/events/intel/p4.c
@@ -947,7 +947,7 @@ static void p4_pmu_enable_pebs(u64 config)
(void)wrmsrl_safe(MSR_P4_PEBS_MATRIX_VERT, (u64)bind->metric_vert);
}
-static void p4_pmu_enable_event(struct perf_event *event)
+static void __p4_pmu_enable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;
int thread = p4_ht_config_thread(hwc->config);
@@ -983,6 +983,16 @@ static void p4_pmu_enable_event(struct perf_event *event)
(cccr & ~P4_CCCR_RESERVED) | P4_CCCR_ENABLE);
}
+static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(X86_PMC_IDX_MAX)], p4_running);
+
+static void p4_pmu_enable_event(struct perf_event *event)
+{
+ int idx = event->hw.idx;
+
+ __set_bit(idx, per_cpu(p4_running, smp_processor_id()));
+ __p4_pmu_enable_event(event);
+}
+
static void p4_pmu_enable_all(int added)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
@@ -992,7 +1002,7 @@ static void p4_pmu_enable_all(int added)
struct perf_event *event = cpuc->events[idx];
if (!test_bit(idx, cpuc->active_mask))
continue;
- p4_pmu_enable_event(event);
+ __p4_pmu_enable_event(event);
}
}
@@ -1012,7 +1022,7 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
if (!test_bit(idx, cpuc->active_mask)) {
/* catch in-flight IRQs */
- if (__test_and_clear_bit(idx, cpuc->running))
+ if (__test_and_clear_bit(idx, per_cpu(p4_running, smp_processor_id())))
handled++;
continue;
}
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 53b2b5f..54a340e 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -228,7 +228,6 @@ struct cpu_hw_events {
*/
struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter order */
unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
- unsigned long running[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
int enabled;
int n_events; /* the # of events in the below arrays */
--
2.7.4
next reply other threads:[~2021-04-13 19:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 18:57 kan.liang [this message]
2021-04-13 18:57 ` [PATCH V3 2/2] perf/x86: Reset the dirty counter to prevent the leak for an RDPMC task kan.liang
2021-04-13 20:33 ` kernel test robot
2021-04-14 13:47 ` Liang, Kan
2021-04-13 23:41 ` kernel test robot
2021-04-14 0:34 ` Andy Lutomirski
2021-04-14 1:30 ` Liang, Kan
2021-04-14 13:51 ` Namhyung Kim
2021-04-14 14:27 ` Liang, Kan
2021-04-14 12:22 ` [PATCH V3 1/2] perf/x86: Move cpuc->running into P4 specific code Peter Zijlstra
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