lkml.org 
[lkml]   [2010]   [Jan]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 08/10] perf_event: Optimize the constraint searching bits
Instead of copying bitmasks around, pass pointers to the constraint structure.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
arch/x86/kernel/cpu/perf_event.c | 81 ++++++++++++++++++---------------------
1 file changed, 38 insertions(+), 43 deletions(-)
Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -135,12 +138,14 @@ struct x86_pmu {
u64 intel_ctrl;
void (*enable_bts)(u64 config);
void (*disable_bts)(void);
- void (*get_event_constraints)(struct cpu_hw_events *cpuc,
- struct perf_event *event,
- unsigned long *idxmsk);
+
+ struct event_constraint *
+ (*get_event_constraints)(struct cpu_hw_events *cpuc,
+ struct perf_event *event);
+
void (*put_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
- const struct event_constraint *event_constraints;
+ struct event_constraint *event_constraints;
};

static struct x86_pmu x86_pmu __read_mostly;
@@ -1244,18 +1249,16 @@ static inline int is_x86_event(struct pe
static int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
{
int i, j , w, num;
- int weight, wmax;
- unsigned long *c;
- unsigned long constraints[X86_PMC_IDX_MAX][BITS_TO_LONGS(X86_PMC_IDX_MAX)];
+ int weight, wmax;
+ struct event_constraint *c, *constraints[X86_PMC_IDX_MAX];
unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
struct hw_perf_event *hwc;

bitmap_zero(used_mask, X86_PMC_IDX_MAX);

for (i = 0; i < n; i++) {
- x86_pmu.get_event_constraints(cpuc,
- cpuc->event_list[i],
- constraints[i]);
+ constraints[i] =
+ x86_pmu.get_event_constraints(cpuc, cpuc->event_list[i]);
}

/*
@@ -1270,7 +1273,7 @@ static int x86_schedule_events(struct cp
break;

/* constraint still honored */
- if (!test_bit(hwc->idx, c))
+ if (!test_bit(hwc->idx, c->idxmsk))
break;

/* not already used */
@@ -1323,11 +1326,11 @@ static int x86_schedule_events(struct cp
c = constraints[i];
hwc = &cpuc->event_list[i]->hw;

- weight = bitmap_weight(c, X86_PMC_IDX_MAX);
+ weight = bitmap_weight(c->idxmsk, X86_PMC_IDX_MAX);
if (weight != w)
continue;

- for_each_bit(j, c, X86_PMC_IDX_MAX) {
+ for_each_bit(j, c->idxmsk, X86_PMC_IDX_MAX) {
if (!test_bit(j, used_mask))
break;
}
@@ -2165,11 +2167,13 @@ perf_event_nmi_handler(struct notifier_b
return NOTIFY_STOP;
}

+static struct event_constraint unconstrained;
+
static struct event_constraint bts_constraint =
EVENT_CONSTRAINT(0, 1ULL << X86_PMC_IDX_FIXED_BTS, 0);

-static int intel_special_constraints(struct perf_event *event,
- unsigned long *idxmsk)
+static struct event_constraint *
+intel_special_constraints(struct perf_event *event)
{
unsigned int hw_event;

@@ -2179,46 +2183,34 @@ static int intel_special_constraints(str
x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS)) &&
(event->hw.sample_period == 1))) {

- bitmap_copy((unsigned long *)idxmsk,
- (unsigned long *)bts_constraint.idxmsk,
- X86_PMC_IDX_MAX);
- return 1;
+ return &bts_constraint;
}
- return 0;
+ return NULL;
}

-static void intel_get_event_constraints(struct cpu_hw_events *cpuc,
- struct perf_event *event,
- unsigned long *idxmsk)
+static struct event_constraint *
+intel_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
{
- const struct event_constraint *c;
+ struct event_constraint *c;

- /*
- * cleanup bitmask
- */
- bitmap_zero(idxmsk, X86_PMC_IDX_MAX);
-
- if (intel_special_constraints(event, idxmsk))
- return;
+ c = intel_special_constraints(event);
+ if (c)
+ return c;

if (x86_pmu.event_constraints) {
for_each_event_constraint(c, x86_pmu.event_constraints) {
- if ((event->hw.config & c->cmask) == c->code) {
- bitmap_copy(idxmsk, c->idxmsk, X86_PMC_IDX_MAX);
- return;
- }
+ if ((event->hw.config & c->cmask) == c->code)
+ return c;
}
}
- /* no constraints, means supports all generic counters */
- bitmap_fill((unsigned long *)idxmsk, x86_pmu.num_events);
+
+ return &unconstrained;
}

-static void amd_get_event_constraints(struct cpu_hw_events *cpuc,
- struct perf_event *event,
- unsigned long *idxmsk)
+static struct event_constraint *
+amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
{
- /* no constraints, means supports all generic counters */
- bitmap_fill(idxmsk, x86_pmu.num_events);
+ return &unconstrained;
}

static int x86_event_sched_in(struct perf_event *event,
@@ -2586,6 +2578,9 @@ void __init init_hw_perf_events(void)
perf_events_lapic_init();
register_die_notifier(&perf_event_nmi_notifier);

+ unconstrained = (struct event_constraint)
+ EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_events) - 1, 0);
+
pr_info("... version: %d\n", x86_pmu.version);
pr_info("... bit width: %d\n", x86_pmu.event_bits);
pr_info("... generic registers: %d\n", x86_pmu.num_events);
--



\
 
 \ /
  Last update: 2010-01-22 17:03    [from the cache]
©2003-2011 Jasper Spaans