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perf: Default PMU ops 

Provide default implementations for the pmu txn methods, this
allows us to remove some conditional code.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: Michael Cree <mcree@orcon.net.nz>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-06-15 12:22:39 +02:00 committed by Ingo Molnar
parent 33696fc0d1
commit ad5133b703
2 changed files with 57 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/linux/perf_event.h
View File

@ -565,8 +565,8 @@ struct pmu {
int *pmu_disable_count;
void (*pmu_enable) (struct pmu *pmu);
void (*pmu_disable) (struct pmu *pmu);
void (*pmu_enable) (struct pmu *pmu); /* optional */
void (*pmu_disable) (struct pmu *pmu); /* optional */
/*
* Should return -ENOENT when the @event doesn't match this PMU.
@ -590,19 +590,19 @@ struct pmu {
* Start the transaction, after this ->enable() doesn't need to
* do schedulability tests.
*/
void (*start_txn) (struct pmu *pmu);
void (*start_txn) (struct pmu *pmu); /* optional */
/*
* 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) (struct pmu *pmu);
int (*commit_txn) (struct pmu *pmu); /* optional */
/*
* Will cancel the transaction, assumes ->disable() is called
* for each successfull ->enable() during the transaction.
*/
void (*cancel_txn) (struct pmu *pmu);
void (*cancel_txn) (struct pmu *pmu); /* optional */
};
/**

64
kernel/perf_event.c
View File

@ -674,21 +674,14 @@ group_sched_in(struct perf_event *group_event,
{
struct perf_event *event, *partial_group = NULL;
struct pmu *pmu = group_event->pmu;
bool txn = false;
if (group_event->state == PERF_EVENT_STATE_OFF)
return 0;
/* Check if group transaction availabe */
if (pmu->start_txn)
txn = true;
if (txn)
pmu->start_txn(pmu);
pmu->start_txn(pmu);
if (event_sched_in(group_event, cpuctx, ctx)) {
if (txn)
pmu->cancel_txn(pmu);
pmu->cancel_txn(pmu);
return -EAGAIN;
}
@ -702,7 +695,7 @@ group_sched_in(struct perf_event *group_event,
}
}
if (!txn || !pmu->commit_txn(pmu))
if (!pmu->commit_txn(pmu))
return 0;
group_error:
@ -717,8 +710,7 @@ group_sched_in(struct perf_event *group_event,
}
event_sched_out(group_event, cpuctx, ctx);
if (txn)
pmu->cancel_txn(pmu);
pmu->cancel_txn(pmu);
return -EAGAIN;
}
@ -4965,6 +4957,31 @@ static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;
static void perf_pmu_nop_void(struct pmu *pmu)
{
}
static int perf_pmu_nop_int(struct pmu *pmu)
{
return 0;
}
static void perf_pmu_start_txn(struct pmu *pmu)
{
perf_pmu_disable(pmu);
}
static int perf_pmu_commit_txn(struct pmu *pmu)
{
perf_pmu_enable(pmu);
return 0;
}
static void perf_pmu_cancel_txn(struct pmu *pmu)
{
perf_pmu_enable(pmu);
}
int perf_pmu_register(struct pmu *pmu)
{
int ret;
@ -4974,6 +4991,29 @@ int perf_pmu_register(struct pmu *pmu)
pmu->pmu_disable_count = alloc_percpu(int);
if (!pmu->pmu_disable_count)
goto unlock;
if (!pmu->start_txn) {
if (pmu->pmu_enable) {
/*
* If we have pmu_enable/pmu_disable calls, install
* transaction stubs that use that to try and batch
* hardware accesses.
*/
pmu->start_txn = perf_pmu_start_txn;
pmu->commit_txn = perf_pmu_commit_txn;
pmu->cancel_txn = perf_pmu_cancel_txn;
} else {
pmu->start_txn = perf_pmu_nop_void;
pmu->commit_txn = perf_pmu_nop_int;
pmu->cancel_txn = perf_pmu_nop_void;
}
}
if (!pmu->pmu_enable) {
pmu->pmu_enable = perf_pmu_nop_void;
pmu->pmu_disable = perf_pmu_nop_void;
}
list_add_rcu(&pmu->entry, &pmus);
ret = 0;
unlock: