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perf/x86: Remove PERF_X86_EVENT_COMMITTED 

The flag PERF_X86_EVENT_COMMITTED is used to find uncommitted events
for which to call put_event_constraint() when scheduling fails.

These are the newly added events to the list, and must form, per
definition, the tail of cpuc->event_list[]. By computing the list
index of the last successfull schedule, then iteration can start there
and the flag is redundant.

There are only 3 callers of x86_schedule_events(), notably:

 - x86_pmu_add()
 - x86_pmu_commit_txn()
 - validate_group()

For x86_pmu_add(), cpuc->n_events isn't updated until after
schedule_events() succeeds, therefore cpuc->n_events points to the
desired index.

For x86_pmu_commit_txn(), cpuc->n_events is updated, but we can
trivially compute the desired value with cpuc->n_txn -- the number of
events added in this transaction.

For validate_group(), we can make the rule for x86_pmu_add() work by
simply setting cpuc->n_events to 0 before calling schedule_events().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2019-03-14 12:58:52 +01:00 committed by Ingo Molnar
parent 21d65555cd
commit 1f6a1e2d7d
2 changed files with 22 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
arch/x86/events/core.c
View File

@ -925,19 +925,23 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
if (!unsched && assign) {
for (i = 0; i < n; i++) {
e = cpuc->event_list[i];
e->hw.flags |= PERF_X86_EVENT_COMMITTED;
if (x86_pmu.commit_scheduling)
x86_pmu.commit_scheduling(cpuc, i, assign[i]);
}
} else {
for (i = 0; i < n; i++) {
/*
* Compute the number of events already present; see
* x86_pmu_add(), validate_group() and x86_pmu_commit_txn().
* For the former two cpuc->n_events hasn't been updated yet,
* while for the latter cpuc->n_txn contains the number of
* events added in the current transaction.
*/
i = cpuc->n_events;
if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
i -= cpuc->n_txn;
for (; i < n; i++) {
e = cpuc->event_list[i];
/*
* do not put_constraint() on comitted events,
* because they are good to go
*/
if ((e->hw.flags & PERF_X86_EVENT_COMMITTED))
continue;
/*
* release events that failed scheduling
@ -1371,11 +1375,6 @@ static void x86_pmu_del(struct perf_event *event, int flags)
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
int i;
/*
* event is descheduled
*/
event->hw.flags &= ~PERF_X86_EVENT_COMMITTED;
/*
* If we're called during a txn, we only need to undo x86_pmu.add.
* The events never got scheduled and ->cancel_txn will truncate
@ -2079,8 +2078,7 @@ static int validate_group(struct perf_event *event)
if (n < 0)
goto out;
fake_cpuc->n_events = n;
fake_cpuc->n_events = 0;
ret = x86_pmu.schedule_events(fake_cpuc, n, NULL);
out:

19
arch/x86/events/perf_event.h
View File

@ -55,22 +55,21 @@ struct event_constraint {
int overlap;
int flags;
};
/*
* struct hw_perf_event.flags flags
*/
#define PERF_X86_EVENT_PEBS_LDLAT 0x0001 /* ld+ldlat data address sampling */
#define PERF_X86_EVENT_PEBS_ST 0x0002 /* st data address sampling */
#define PERF_X86_EVENT_PEBS_ST_HSW 0x0004 /* haswell style datala, store */
#define PERF_X86_EVENT_COMMITTED 0x0008 /* event passed commit_txn */
#define PERF_X86_EVENT_PEBS_LD_HSW 0x0010 /* haswell style datala, load */
#define PERF_X86_EVENT_PEBS_NA_HSW 0x0020 /* haswell style datala, unknown */
#define PERF_X86_EVENT_EXCL 0x0040 /* HT exclusivity on counter */
#define PERF_X86_EVENT_DYNAMIC 0x0080 /* dynamic alloc'd constraint */
#define PERF_X86_EVENT_RDPMC_ALLOWED 0x0100 /* grant rdpmc permission */
#define PERF_X86_EVENT_EXCL_ACCT 0x0200 /* accounted EXCL event */
#define PERF_X86_EVENT_AUTO_RELOAD 0x0400 /* use PEBS auto-reload */
#define PERF_X86_EVENT_LARGE_PEBS 0x0800 /* use large PEBS */
#define PERF_X86_EVENT_PEBS_LD_HSW 0x0008 /* haswell style datala, load */
#define PERF_X86_EVENT_PEBS_NA_HSW 0x0010 /* haswell style datala, unknown */
#define PERF_X86_EVENT_EXCL 0x0020 /* HT exclusivity on counter */
#define PERF_X86_EVENT_DYNAMIC 0x0040 /* dynamic alloc'd constraint */
#define PERF_X86_EVENT_RDPMC_ALLOWED 0x0080 /* grant rdpmc permission */
#define PERF_X86_EVENT_EXCL_ACCT 0x0100 /* accounted EXCL event */
#define PERF_X86_EVENT_AUTO_RELOAD 0x0200 /* use PEBS auto-reload */
#define PERF_X86_EVENT_LARGE_PEBS 0x0400 /* use large PEBS */
struct amd_nb {
int nb_id; /* NorthBridge id */