[tip:perf/core] x86, perf: P4 PMU -- use hash for p4_get_escr_idx()

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Commit-ID:  720019908fd5a1bb442bb0a35a6027ba21864d25
Gitweb:     http://git.kernel.org/tip/720019908fd5a1bb442bb0a35a6027ba21864d25
Author:     Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
AuthorDate: Wed, 12 May 2010 21:42:42 +0400
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 13 May 2010 08:51:13 +0200

x86, perf: P4 PMU -- use hash for p4_get_escr_idx()

Linear search over all p4 MSRs should be fine if only
we would not use it in events scheduling routine which
is pretty time critical. Lets use hashes. It should speed
scheduling up significantly.

v2: Steven proposed to use more gentle approach than issue
    BUG on error, so we use WARN_ONCE now

Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Lin Ming <ming.m.lin@xxxxxxxxx>
LKML-Reference: <20100512174242.GA5190@lenovo>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
 arch/x86/kernel/cpu/perf_event_p4.c |  126 ++++++++++++++++++++---------------
 1 files changed, 71 insertions(+), 55 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index a603930..cb875b1 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -668,66 +668,80 @@ static void p4_pmu_swap_config_ts(struct hw_perf_event *hwc, int cpu)
 	}
 }
 
-/* ESCRs are not sequential in memory so we need a map */
-static const unsigned int p4_escr_map[ARCH_P4_TOTAL_ESCR] = {
-	MSR_P4_ALF_ESCR0,	/*  0 */
-	MSR_P4_ALF_ESCR1,	/*  1 */
-	MSR_P4_BPU_ESCR0,	/*  2 */
-	MSR_P4_BPU_ESCR1,	/*  3 */
-	MSR_P4_BSU_ESCR0,	/*  4 */
-	MSR_P4_BSU_ESCR1,	/*  5 */
-	MSR_P4_CRU_ESCR0,	/*  6 */
-	MSR_P4_CRU_ESCR1,	/*  7 */
-	MSR_P4_CRU_ESCR2,	/*  8 */
-	MSR_P4_CRU_ESCR3,	/*  9 */
-	MSR_P4_CRU_ESCR4,	/* 10 */
-	MSR_P4_CRU_ESCR5,	/* 11 */
-	MSR_P4_DAC_ESCR0,	/* 12 */
-	MSR_P4_DAC_ESCR1,	/* 13 */
-	MSR_P4_FIRM_ESCR0,	/* 14 */
-	MSR_P4_FIRM_ESCR1,	/* 15 */
-	MSR_P4_FLAME_ESCR0,	/* 16 */
-	MSR_P4_FLAME_ESCR1,	/* 17 */
-	MSR_P4_FSB_ESCR0,	/* 18 */
-	MSR_P4_FSB_ESCR1,	/* 19 */
-	MSR_P4_IQ_ESCR0,	/* 20 */
-	MSR_P4_IQ_ESCR1,	/* 21 */
-	MSR_P4_IS_ESCR0,	/* 22 */
-	MSR_P4_IS_ESCR1,	/* 23 */
-	MSR_P4_ITLB_ESCR0,	/* 24 */
-	MSR_P4_ITLB_ESCR1,	/* 25 */
-	MSR_P4_IX_ESCR0,	/* 26 */
-	MSR_P4_IX_ESCR1,	/* 27 */
-	MSR_P4_MOB_ESCR0,	/* 28 */
-	MSR_P4_MOB_ESCR1,	/* 29 */
-	MSR_P4_MS_ESCR0,	/* 30 */
-	MSR_P4_MS_ESCR1,	/* 31 */
-	MSR_P4_PMH_ESCR0,	/* 32 */
-	MSR_P4_PMH_ESCR1,	/* 33 */
-	MSR_P4_RAT_ESCR0,	/* 34 */
-	MSR_P4_RAT_ESCR1,	/* 35 */
-	MSR_P4_SAAT_ESCR0,	/* 36 */
-	MSR_P4_SAAT_ESCR1,	/* 37 */
-	MSR_P4_SSU_ESCR0,	/* 38 */
-	MSR_P4_SSU_ESCR1,	/* 39 */
-	MSR_P4_TBPU_ESCR0,	/* 40 */
-	MSR_P4_TBPU_ESCR1,	/* 41 */
-	MSR_P4_TC_ESCR0,	/* 42 */
-	MSR_P4_TC_ESCR1,	/* 43 */
-	MSR_P4_U2L_ESCR0,	/* 44 */
-	MSR_P4_U2L_ESCR1,	/* 45 */
+/*
+ * ESCR address hashing is tricky, ESCRs are not sequential
+ * in memory but all starts from MSR_P4_BSU_ESCR0 (0x03e0) and
+ * the metric between any ESCRs is laid in range [0xa0,0xe1]
+ *
+ * so we make ~70% filled hashtable
+ */
+
+#define P4_ESCR_MSR_BASE		0x000003a0
+#define P4_ESCR_MSR_MAX			0x000003e1
+#define P4_ESCR_MSR_TABLE_SIZE		(P4_ESCR_MSR_MAX - P4_ESCR_MSR_BASE + 1)
+#define P4_ESCR_MSR_IDX(msr)		(msr - P4_ESCR_MSR_BASE)
+#define P4_ESCR_MSR_TABLE_ENTRY(msr)	[P4_ESCR_MSR_IDX(msr)] = msr
+
+static const unsigned int p4_escr_table[P4_ESCR_MSR_TABLE_SIZE] = {
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_ALF_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_ALF_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_BPU_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_BPU_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_BSU_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_BSU_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_CRU_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_CRU_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_CRU_ESCR2),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_CRU_ESCR3),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_CRU_ESCR4),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_CRU_ESCR5),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_DAC_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_DAC_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_FIRM_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_FIRM_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_FLAME_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_FLAME_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_FSB_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_FSB_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_IQ_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_IQ_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_IS_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_IS_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_ITLB_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_ITLB_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_IX_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_IX_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_MOB_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_MOB_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_MS_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_MS_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_PMH_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_PMH_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_RAT_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_RAT_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_SAAT_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_SAAT_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_SSU_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_SSU_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_TBPU_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_TBPU_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_TC_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_TC_ESCR1),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_U2L_ESCR0),
+	P4_ESCR_MSR_TABLE_ENTRY(MSR_P4_U2L_ESCR1),
 };
 
 static int p4_get_escr_idx(unsigned int addr)
 {
-	unsigned int i;
+	unsigned int idx = P4_ESCR_MSR_IDX(addr);
 
-	for (i = 0; i < ARRAY_SIZE(p4_escr_map); i++) {
-		if (addr == p4_escr_map[i])
-			return i;
+	if (unlikely(idx >= P4_ESCR_MSR_TABLE_SIZE ||
+			!p4_escr_table[idx])) {
+		WARN_ONCE(1, "P4 PMU: Wrong address passed: %x\n", addr);
+		return -1;
 	}
 
-	return -1;
+	return idx;
 }
 
 static int p4_next_cntr(int thread, unsigned long *used_mask,
@@ -747,7 +761,7 @@ static int p4_next_cntr(int thread, unsigned long *used_mask,
 static int p4_pmu_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
 {
 	unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
-	unsigned long escr_mask[BITS_TO_LONGS(ARCH_P4_TOTAL_ESCR)];
+	unsigned long escr_mask[BITS_TO_LONGS(P4_ESCR_MSR_TABLE_SIZE)];
 	int cpu = raw_smp_processor_id();
 	struct hw_perf_event *hwc;
 	struct p4_event_bind *bind;
@@ -755,7 +769,7 @@ static int p4_pmu_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign
 	int cntr_idx, escr_idx;
 
 	bitmap_zero(used_mask, X86_PMC_IDX_MAX);
-	bitmap_zero(escr_mask, ARCH_P4_TOTAL_ESCR);
+	bitmap_zero(escr_mask, P4_ESCR_MSR_TABLE_SIZE);
 
 	for (i = 0, num = n; i < n; i++, num--) {
 
@@ -763,6 +777,8 @@ static int p4_pmu_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign
 		thread = p4_ht_thread(cpu);
 		bind = p4_config_get_bind(hwc->config);
 		escr_idx = p4_get_escr_idx(bind->escr_msr[thread]);
+		if (unlikely(escr_idx == -1))
+			goto done;
 
 		if (hwc->idx != -1 && !p4_should_swap_ts(hwc->config, cpu)) {
 			cntr_idx = hwc->idx;
--
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