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perf: Rework the PMU methods

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Replace pmu::{enable,disable,start,stop,unthrottle} with
pmu::{add,del,start,stop}, all of which take a flags argument.

The new interface extends the capability to stop a counter while
keeping it scheduled on the PMU. We replace the throttled state with
the generic stopped state.

This also allows us to efficiently stop/start counters over certain
code paths (like IRQ handlers).

It also allows scheduling a counter without it starting, allowing for
a generic frozen state (useful for rotating stopped counters).

The stopped state is implemented in two different ways, depending on
how the architecture implemented the throttled state:

 1) We disable the counter:
    a) the pmu has per-counter enable bits, we flip that
    b) we program a NOP event, preserving the counter state

 2) We store the counter state and ignore all read/overflow events

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
2010-06-16 14:37:10 +02:00
committed by Ingo Molnar
parent fa407f35e0
commit a4eaf7f146
14 changed files with 599 additions and 354 deletions
Download Patch File Download Diff File Expand all files Collapse all files

106
arch/x86/kernel/cpu/perf_event.c
View File

@@ -583,7 +583,7 @@ static void x86_pmu_disable_all(void)
}
}
static void x86_pmu_pmu_disable(struct pmu *pmu)
static void x86_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -800,10 +800,10 @@ static inline int match_prev_assignment(struct hw_perf_event *hwc,
hwc->last_tag == cpuc->tags[i];
}
static int x86_pmu_start(struct perf_event *event);
static void x86_pmu_stop(struct perf_event *event);
static void x86_pmu_start(struct perf_event *event, int flags);
static void x86_pmu_stop(struct perf_event *event, int flags);
static void x86_pmu_pmu_enable(struct pmu *pmu)
static void x86_pmu_enable(struct pmu *pmu)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct perf_event *event;
@@ -839,7 +839,14 @@ static void x86_pmu_pmu_enable(struct pmu *pmu)
match_prev_assignment(hwc, cpuc, i))
continue;
x86_pmu_stop(event);
/*
* Ensure we don't accidentally enable a stopped
* counter simply because we rescheduled.
*/
if (hwc->state & PERF_HES_STOPPED)
hwc->state |= PERF_HES_ARCH;
x86_pmu_stop(event, PERF_EF_UPDATE);
}
for (i = 0; i < cpuc->n_events; i++) {
@@ -851,7 +858,10 @@ static void x86_pmu_pmu_enable(struct pmu *pmu)
else if (i < n_running)
continue;
x86_pmu_start(event);
if (hwc->state & PERF_HES_ARCH)
continue;
x86_pmu_start(event, PERF_EF_RELOAD);
}
cpuc->n_added = 0;
perf_events_lapic_init();
@@ -952,15 +962,12 @@ static void x86_pmu_enable_event(struct perf_event *event)
}
/*
* activate a single event
* Add a single event to the PMU.
*
* The event is added to the group of enabled events
* but only if it can be scehduled with existing events.
*
* Called with PMU disabled. If successful and return value 1,
* then guaranteed to call perf_enable() and hw_perf_enable()
*/
static int x86_pmu_enable(struct perf_event *event)
static int x86_pmu_add(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc;
@@ -975,10 +982,14 @@ static int x86_pmu_enable(struct perf_event *event)
if (ret < 0)
goto out;
hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
if (!(flags & PERF_EF_START))
hwc->state |= PERF_HES_ARCH;
/*
* If group events scheduling transaction was started,
* skip the schedulability test here, it will be peformed
* at commit time(->commit_txn) as a whole
* at commit time (->commit_txn) as a whole
*/
if (cpuc->group_flag & PERF_EVENT_TXN)
goto done_collect;
@@ -1003,27 +1014,28 @@ out:
return ret;
}
static int x86_pmu_start(struct perf_event *event)
static void x86_pmu_start(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx = event->hw.idx;
if (idx == -1)
return -EAGAIN;
if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
return;
if (WARN_ON_ONCE(idx == -1))
return;
if (flags & PERF_EF_RELOAD) {
WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
x86_perf_event_set_period(event);
}
event->hw.state = 0;
x86_perf_event_set_period(event);
cpuc->events[idx] = event;
__set_bit(idx, cpuc->active_mask);
x86_pmu.enable(event);
perf_event_update_userpage(event);
return 0;
}
static void x86_pmu_unthrottle(struct perf_event *event)
{
int ret = x86_pmu_start(event);
WARN_ON_ONCE(ret);
}
void perf_event_print_debug(void)
@@ -1080,27 +1092,29 @@ void perf_event_print_debug(void)
local_irq_restore(flags);
}
static void x86_pmu_stop(struct perf_event *event)
static void x86_pmu_stop(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
int idx = hwc->idx;
if (!__test_and_clear_bit(idx, cpuc->active_mask))
return;
if (__test_and_clear_bit(hwc->idx, cpuc->active_mask)) {
x86_pmu.disable(event);
cpuc->events[hwc->idx] = NULL;
WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
hwc->state |= PERF_HES_STOPPED;
}
x86_pmu.disable(event);
/*
* Drain the remaining delta count out of a event
* that we are disabling:
*/
x86_perf_event_update(event);
cpuc->events[idx] = NULL;
if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
/*
* Drain the remaining delta count out of a event
* that we are disabling:
*/
x86_perf_event_update(event);
hwc->state |= PERF_HES_UPTODATE;
}
}
static void x86_pmu_disable(struct perf_event *event)
static void x86_pmu_del(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int i;
@@ -1113,7 +1127,7 @@ static void x86_pmu_disable(struct perf_event *event)
if (cpuc->group_flag & PERF_EVENT_TXN)
return;
x86_pmu_stop(event);
x86_pmu_stop(event, PERF_EF_UPDATE);
for (i = 0; i < cpuc->n_events; i++) {
if (event == cpuc->event_list[i]) {
@@ -1165,7 +1179,7 @@ static int x86_pmu_handle_irq(struct pt_regs *regs)
continue;
if (perf_event_overflow(event, 1, &data, regs))
x86_pmu_stop(event);
x86_pmu_stop(event, 0);
}
if (handled)
@@ -1605,15 +1619,17 @@ int x86_pmu_event_init(struct perf_event *event)
}
static struct pmu pmu = {
.pmu_enable = x86_pmu_pmu_enable,
.pmu_disable = x86_pmu_pmu_disable,
.pmu_enable = x86_pmu_enable,
.pmu_disable = x86_pmu_disable,
.event_init = x86_pmu_event_init,
.enable = x86_pmu_enable,
.disable = x86_pmu_disable,
.add = x86_pmu_add,
.del = x86_pmu_del,
.start = x86_pmu_start,
.stop = x86_pmu_stop,
.read = x86_pmu_read,
.unthrottle = x86_pmu_unthrottle,
.start_txn = x86_pmu_start_txn,
.cancel_txn = x86_pmu_cancel_txn,
.commit_txn = x86_pmu_commit_txn,