Messages in this thread Patch in this message | | | From | Stephane Eranian <> | Subject | [PATCH 05/12] perf_events: add LBR mappings for PERF_SAMPLE_BRANCH filters (v2) | Date | Fri, 14 Oct 2011 14:37:06 +0200 |
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This patch adds the mappings from the generic PERF_SAMPLE_BRANCH_* filters to the actual Intel X86 LBR filters, whenever they exist.
The patch also adds a restriction on Intel Atom, whereby only stepping 10 (PineView) and more recent are supported. Older models, do not have a functional LBR (does not freeze on PMU interrupt).
Signed-off-by: Stephane Eranian <eranian@google.com> --- arch/x86/kernel/cpu/perf_event.h | 2 + arch/x86/kernel/cpu/perf_event_intel.c | 2 +- arch/x86/kernel/cpu/perf_event_intel_lbr.c | 110 +++++++++++++++++++++++++++- 3 files changed, 111 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h index 8a5c21f..750c7af 100644 --- a/arch/x86/kernel/cpu/perf_event.h +++ b/arch/x86/kernel/cpu/perf_event.h @@ -482,6 +482,8 @@ void intel_pmu_lbr_init_nhm(void); void intel_pmu_lbr_init_atom(void); +void intel_pmu_lbr_init_snb(void); + int p4_pmu_init(void); int p6_pmu_init(void); diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 1303732..6f313c0 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1715,7 +1715,7 @@ __init int intel_pmu_init(void) memcpy(hw_cache_event_ids, snb_hw_cache_event_ids, sizeof(hw_cache_event_ids)); - intel_pmu_lbr_init_nhm(); + intel_pmu_lbr_init_snb(); x86_pmu.event_constraints = intel_snb_event_constraints; x86_pmu.pebs_constraints = intel_snb_pebs_event_constraints; diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c index e9ac6e9..2e56ed3 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c @@ -14,6 +14,47 @@ enum { }; /* + * Intel LBR_SELECT bits + * Intel Vol3a, April 2011, Section 16.7 Table 16-10 + * + * Hardware branch filter (not available on all CPUs) + */ +#define LBR_KERNEL_BIT 0 /* do not capture at ring0 */ +#define LBR_USER_BIT 1 /* do not capture at ring > 0 */ +#define LBR_JCC_BIT 2 /* do not capture conditional branches */ +#define LBR_REL_CALL_BIT 3 /* do not capture relative calls */ +#define LBR_IND_CALL_BIT 4 /* do not capture indirect calls */ +#define LBR_RETURN_BIT 5 /* do not capture near returns */ +#define LBR_IND_JMP_BIT 6 /* do not capture indirect jumps */ +#define LBR_REL_JMP_BIT 7 /* do not capture relative jumps */ +#define LBR_FAR_BIT 8 /* do not capture far branches */ + +#define LBR_KERNEL (1 << LBR_KERNEL_BIT) +#define LBR_USER (1 << LBR_USER_BIT) +#define LBR_JCC (1 << LBR_JCC_BIT) +#define LBR_REL_CALL (1 << LBR_REL_CALL_BIT) +#define LBR_IND_CALL (1 << LBR_IND_CALL_BIT) +#define LBR_RETURN (1 << LBR_RETURN_BIT) +#define LBR_REL_JMP (1 << LBR_REL_JMP_BIT) +#define LBR_IND_JMP (1 << LBR_IND_JMP_BIT) +#define LBR_FAR (1 << LBR_FAR_BIT) + +#define LBR_PLM (LBR_KERNEL | LBR_USER) + +#define LBR_SEL_MASK 0x1ff /* valid bits in LBR_SELECT */ + +#define LBR_ANY \ + (LBR_JCC |\ + LBR_REL_CALL |\ + LBR_IND_CALL |\ + LBR_RETURN |\ + LBR_REL_JMP |\ + LBR_IND_JMP |\ + LBR_FAR) + +#define LBR_FROM_FLAG_MISPRED (1ULL << 63) + +/* * We only support LBR implementations that have FREEZE_LBRS_ON_PMI * otherwise it becomes near impossible to get a reliable stack. */ @@ -153,8 +194,6 @@ static void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc) cpuc->lbr_stack.nr = i; } -#define LBR_FROM_FLAG_MISPRED (1ULL << 63) - /* * Due to lack of segmentation in Linux the effective address (offset) * is the same as the linear address, allowing us to merge the LIP and EIP @@ -202,26 +241,93 @@ void intel_pmu_lbr_read(void) intel_pmu_lbr_read_64(cpuc); } +/* + * Map interface branch filters onto LBR filters + */ +static const int nhm_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX]= +{ + [PERF_SAMPLE_BRANCH_ANY] = LBR_ANY, + [PERF_SAMPLE_BRANCH_USER] = LBR_USER, + [PERF_SAMPLE_BRANCH_KERNEL] = LBR_KERNEL, + [PERF_SAMPLE_BRANCH_ANY_RETURN] = + LBR_RETURN | LBR_REL_JMP | LBR_IND_JMP | LBR_FAR, + /* + * NHM/WSM erratum: must include REL_JMP+IND_JMP to get CALL branches + */ + [PERF_SAMPLE_BRANCH_ANY_CALL] = + LBR_REL_CALL | LBR_IND_CALL | LBR_REL_JMP | LBR_IND_JMP | LBR_FAR, + /* + * NHM/WSM erratum: must include IND_JMP to capture IND_CALL + */ + [PERF_SAMPLE_BRANCH_IND_CALL] = LBR_IND_CALL | LBR_IND_JMP, +}; + +static const int snb_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX]= +{ + [PERF_SAMPLE_BRANCH_ANY] = LBR_ANY, + [PERF_SAMPLE_BRANCH_USER] = LBR_USER, + [PERF_SAMPLE_BRANCH_KERNEL] = LBR_KERNEL, + [PERF_SAMPLE_BRANCH_ANY_RETURN] = LBR_RETURN | LBR_FAR, + [PERF_SAMPLE_BRANCH_ANY_CALL] = LBR_REL_CALL | LBR_IND_CALL | LBR_FAR, + [PERF_SAMPLE_BRANCH_IND_CALL] = LBR_IND_CALL, +}; + +/* core */ void intel_pmu_lbr_init_core(void) { x86_pmu.lbr_nr = 4; x86_pmu.lbr_tos = MSR_LBR_TOS; x86_pmu.lbr_from = MSR_LBR_CORE_FROM; x86_pmu.lbr_to = MSR_LBR_CORE_TO; + + pr_cont("4-deep LBR, "); } +/* nehalem/westmere */ void intel_pmu_lbr_init_nhm(void) { x86_pmu.lbr_nr = 16; x86_pmu.lbr_tos = MSR_LBR_TOS; x86_pmu.lbr_from = MSR_LBR_NHM_FROM; x86_pmu.lbr_to = MSR_LBR_NHM_TO; + + x86_pmu.lbr_sel_mask = LBR_SEL_MASK; + x86_pmu.lbr_sel_map = nhm_lbr_sel_map; + + pr_cont("16-deep LBR, "); +} + +/* sandy bridge */ +void intel_pmu_lbr_init_snb(void) +{ + x86_pmu.lbr_nr = 16; + x86_pmu.lbr_tos = MSR_LBR_TOS; + x86_pmu.lbr_from = MSR_LBR_NHM_FROM; + x86_pmu.lbr_to = MSR_LBR_NHM_TO; + + x86_pmu.lbr_sel_mask = LBR_SEL_MASK; + x86_pmu.lbr_sel_map = snb_lbr_sel_map; + + pr_cont("16-deep LBR, "); } +/* atom */ void intel_pmu_lbr_init_atom(void) { + /* + * only models starting at stepping 10 seems + * to have an operational LBR which can freeze + * on PMU interrupt + */ + if (boot_cpu_data.x86_mask < 10) { + pr_cont("LBR disabled due to erratum"); + return; + } + x86_pmu.lbr_nr = 8; x86_pmu.lbr_tos = MSR_LBR_TOS; x86_pmu.lbr_from = MSR_LBR_CORE_FROM; x86_pmu.lbr_to = MSR_LBR_CORE_TO; + + pr_cont("8-deep LBR, "); } -- 1.7.1
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