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Date: Wed, 9 Jun 2010 10:15:50 GMT
From: tip-bot for Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, paulus@...ba.org, acme@...hat.com,
hpa@...or.com, mingo@...hat.com, a.p.zijlstra@...llo.nl,
efault@....de, fweisbec@...il.com, rostedt@...dmis.org,
tglx@...utronix.de, mingo@...e.hu
Subject: [tip:perf/core] perf: Cleanup {start,commit,cancel}_txn details
Commit-ID: 8d2cacbbb8deadfae78aa16e4e1ee619bdd7019e
Gitweb: http://git.kernel.org/tip/8d2cacbbb8deadfae78aa16e4e1ee619bdd7019e
Author: Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Tue, 25 May 2010 17:49:05 +0200
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Wed, 9 Jun 2010 11:12:34 +0200
perf: Cleanup {start,commit,cancel}_txn details
Clarify some of the transactional group scheduling API details
and change it so that a successfull ->commit_txn also closes
the transaction.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Mike Galbraith <efault@....de>
Cc: Steven Rostedt <rostedt@...dmis.org>
LKML-Reference: <1274803086.5882.1752.camel@...ns>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
arch/powerpc/kernel/perf_event.c | 7 ++++---
arch/sparc/kernel/perf_event.c | 7 ++++---
arch/x86/kernel/cpu/perf_event.c | 14 +++++---------
include/linux/perf_event.h | 27 ++++++++++++++++++++++-----
kernel/perf_event.c | 9 +--------
5 files changed, 36 insertions(+), 28 deletions(-)
diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c
index 43b83c3..ac2a8c2 100644
--- a/arch/powerpc/kernel/perf_event.c
+++ b/arch/powerpc/kernel/perf_event.c
@@ -754,7 +754,7 @@ static int power_pmu_enable(struct perf_event *event)
* skip the schedulability test here, it will be peformed
* at commit time(->commit_txn) as a whole
*/
- if (cpuhw->group_flag & PERF_EVENT_TXN_STARTED)
+ if (cpuhw->group_flag & PERF_EVENT_TXN)
goto nocheck;
if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
@@ -858,7 +858,7 @@ void power_pmu_start_txn(const struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
- cpuhw->group_flag |= PERF_EVENT_TXN_STARTED;
+ cpuhw->group_flag |= PERF_EVENT_TXN;
cpuhw->n_txn_start = cpuhw->n_events;
}
@@ -871,7 +871,7 @@ void power_pmu_cancel_txn(const struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
- cpuhw->group_flag &= ~PERF_EVENT_TXN_STARTED;
+ cpuhw->group_flag &= ~PERF_EVENT_TXN;
}
/*
@@ -897,6 +897,7 @@ int power_pmu_commit_txn(const struct pmu *pmu)
for (i = cpuhw->n_txn_start; i < n; ++i)
cpuhw->event[i]->hw.config = cpuhw->events[i];
+ cpuhw->group_flag &= ~PERF_EVENT_TXN;
return 0;
}
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 0ec92c8..beeb92f 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1005,7 +1005,7 @@ static int sparc_pmu_enable(struct perf_event *event)
* skip the schedulability test here, it will be peformed
* at commit time(->commit_txn) as a whole
*/
- if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
+ if (cpuc->group_flag & PERF_EVENT_TXN)
goto nocheck;
if (check_excludes(cpuc->event, n0, 1))
@@ -1102,7 +1102,7 @@ static void sparc_pmu_start_txn(const struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
- cpuhw->group_flag |= PERF_EVENT_TXN_STARTED;
+ cpuhw->group_flag |= PERF_EVENT_TXN;
}
/*
@@ -1114,7 +1114,7 @@ static void sparc_pmu_cancel_txn(const struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
- cpuhw->group_flag &= ~PERF_EVENT_TXN_STARTED;
+ cpuhw->group_flag &= ~PERF_EVENT_TXN;
}
/*
@@ -1137,6 +1137,7 @@ static int sparc_pmu_commit_txn(const struct pmu *pmu)
if (sparc_check_constraints(cpuc->event, cpuc->events, n))
return -EAGAIN;
+ cpuc->group_flag &= ~PERF_EVENT_TXN;
return 0;
}
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 5db5b7d..af04c6f 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -969,7 +969,7 @@ static int x86_pmu_enable(struct perf_event *event)
* skip the schedulability test here, it will be peformed
* at commit time(->commit_txn) as a whole
*/
- if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
+ if (cpuc->group_flag & PERF_EVENT_TXN)
goto out;
ret = x86_pmu.schedule_events(cpuc, n, assign);
@@ -1096,7 +1096,7 @@ static void x86_pmu_disable(struct perf_event *event)
* The events never got scheduled and ->cancel_txn will truncate
* the event_list.
*/
- if (cpuc->group_flag & PERF_EVENT_TXN_STARTED)
+ if (cpuc->group_flag & PERF_EVENT_TXN)
return;
x86_pmu_stop(event);
@@ -1388,7 +1388,7 @@ static void x86_pmu_start_txn(const struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- cpuc->group_flag |= PERF_EVENT_TXN_STARTED;
+ cpuc->group_flag |= PERF_EVENT_TXN;
cpuc->n_txn = 0;
}
@@ -1401,7 +1401,7 @@ static void x86_pmu_cancel_txn(const struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- cpuc->group_flag &= ~PERF_EVENT_TXN_STARTED;
+ cpuc->group_flag &= ~PERF_EVENT_TXN;
/*
* Truncate the collected events.
*/
@@ -1435,11 +1435,7 @@ static int x86_pmu_commit_txn(const struct pmu *pmu)
*/
memcpy(cpuc->assign, assign, n*sizeof(int));
- /*
- * Clear out the txn count so that ->cancel_txn() which gets
- * run after ->commit_txn() doesn't undo things.
- */
- cpuc->n_txn = 0;
+ cpuc->group_flag &= ~PERF_EVENT_TXN;
return 0;
}
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 36efad9..f1b6ba0 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -549,7 +549,10 @@ struct hw_perf_event {
struct perf_event;
-#define PERF_EVENT_TXN_STARTED 1
+/*
+ * Common implementation detail of pmu::{start,commit,cancel}_txn
+ */
+#define PERF_EVENT_TXN 0x1
/**
* struct pmu - generic performance monitoring unit
@@ -563,14 +566,28 @@ struct pmu {
void (*unthrottle) (struct perf_event *event);
/*
- * group events scheduling is treated as a transaction,
- * add group events as a whole and perform one schedulability test.
- * If test fails, roll back the whole group
+ * Group events scheduling is treated as a transaction, add group
+ * events as a whole and perform one schedulability test. If the test
+ * fails, roll back the whole group
*/
+ /*
+ * Start the transaction, after this ->enable() doesn't need
+ * to do schedulability tests.
+ */
void (*start_txn) (const struct pmu *pmu);
- void (*cancel_txn) (const struct pmu *pmu);
+ /*
+ * If ->start_txn() disabled the ->enable() schedulability test
+ * then ->commit_txn() is required to perform one. On success
+ * the transaction is closed. On error the transaction is kept
+ * open until ->cancel_txn() is called.
+ */
int (*commit_txn) (const struct pmu *pmu);
+ /*
+ * Will cancel the transaction, assumes ->disable() is called for
+ * each successfull ->enable() during the transaction.
+ */
+ void (*cancel_txn) (const struct pmu *pmu);
};
/**
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 227ed9c..6f60920 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -675,7 +675,6 @@ group_sched_in(struct perf_event *group_event,
struct perf_event *event, *partial_group = NULL;
const struct pmu *pmu = group_event->pmu;
bool txn = false;
- int ret;
if (group_event->state == PERF_EVENT_STATE_OFF)
return 0;
@@ -703,15 +702,9 @@ group_sched_in(struct perf_event *group_event,
}
}
- if (!txn)
+ if (!txn || !pmu->commit_txn(pmu))
return 0;
- ret = pmu->commit_txn(pmu);
- if (!ret) {
- pmu->cancel_txn(pmu);
- return 0;
- }
-
group_error:
/*
* Groups can be scheduled in as one unit only, so undo any
--
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