diff options
| -rw-r--r-- | arch/x86/events/amd/brs.c | 69 | ||||
| -rw-r--r-- | arch/x86/events/amd/core.c | 70 | ||||
| -rw-r--r-- | arch/x86/events/perf_event.h | 7 |
3 files changed, 76 insertions, 70 deletions
diff --git a/arch/x86/events/amd/brs.c b/arch/x86/events/amd/brs.c index bee8765a1e9b..f1bff153d945 100644 --- a/arch/x86/events/amd/brs.c +++ b/arch/x86/events/amd/brs.c @@ -81,7 +81,7 @@ static bool __init amd_brs_detect(void) * a br_sel_map. Software filtering is not supported because it would not correlate well * with a sampling period. */ -int amd_brs_setup_filter(struct perf_event *event) +static int amd_brs_setup_filter(struct perf_event *event) { u64 type = event->attr.branch_sample_type; @@ -96,6 +96,73 @@ int amd_brs_setup_filter(struct perf_event *event) return 0; } +static inline int amd_is_brs_event(struct perf_event *e) +{ + return (e->hw.config & AMD64_RAW_EVENT_MASK) == AMD_FAM19H_BRS_EVENT; +} + +int amd_brs_hw_config(struct perf_event *event) +{ + int ret = 0; + + /* + * Due to interrupt holding, BRS is not recommended in + * counting mode. + */ + if (!is_sampling_event(event)) + return -EINVAL; + + /* + * Due to the way BRS operates by holding the interrupt until + * lbr_nr entries have been captured, it does not make sense + * to allow sampling on BRS with an event that does not match + * what BRS is capturing, i.e., retired taken branches. + * Otherwise the correlation with the event's period is even + * more loose: + * + * With retired taken branch: + * Effective P = P + 16 + X + * With any other event: + * Effective P = P + Y + X + * + * Where X is the number of taken branches due to interrupt + * skid. Skid is large. + * + * Where Y is the occurences of the event while BRS is + * capturing the lbr_nr entries. + * + * By using retired taken branches, we limit the impact on the + * Y variable. We know it cannot be more than the depth of + * BRS. + */ + if (!amd_is_brs_event(event)) + return -EINVAL; + + /* + * BRS implementation does not work with frequency mode + * reprogramming of the period. + */ + if (event->attr.freq) + return -EINVAL; + /* + * The kernel subtracts BRS depth from period, so it must + * be big enough. + */ + if (event->attr.sample_period <= x86_pmu.lbr_nr) + return -EINVAL; + + /* + * Check if we can allow PERF_SAMPLE_BRANCH_STACK + */ + ret = amd_brs_setup_filter(event); + + /* only set in case of success */ + if (!ret) + event->hw.flags |= PERF_X86_EVENT_AMD_BRS; + + return ret; +} + /* tos = top of stack, i.e., last valid entry written */ static inline int amd_brs_get_tos(union amd_debug_extn_cfg *cfg) { diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c index 9ac3718410ce..e32a27899e11 100644 --- a/arch/x86/events/amd/core.c +++ b/arch/x86/events/amd/core.c @@ -330,16 +330,8 @@ static inline bool amd_is_pair_event_code(struct hw_perf_event *hwc) } } -#define AMD_FAM19H_BRS_EVENT 0xc4 /* RETIRED_TAKEN_BRANCH_INSTRUCTIONS */ -static inline int amd_is_brs_event(struct perf_event *e) -{ - return (e->hw.config & AMD64_RAW_EVENT_MASK) == AMD_FAM19H_BRS_EVENT; -} - static int amd_core_hw_config(struct perf_event *event) { - int ret = 0; - if (event->attr.exclude_host && event->attr.exclude_guest) /* * When HO == GO == 1 the hardware treats that as GO == HO == 0 @@ -356,66 +348,10 @@ static int amd_core_hw_config(struct perf_event *event) if ((x86_pmu.flags & PMU_FL_PAIR) && amd_is_pair_event_code(&event->hw)) event->hw.flags |= PERF_X86_EVENT_PAIR; - /* - * if branch stack is requested - */ - if (has_branch_stack(event)) { - /* - * Due to interrupt holding, BRS is not recommended in - * counting mode. - */ - if (!is_sampling_event(event)) - return -EINVAL; - - /* - * Due to the way BRS operates by holding the interrupt until - * lbr_nr entries have been captured, it does not make sense - * to allow sampling on BRS with an event that does not match - * what BRS is capturing, i.e., retired taken branches. - * Otherwise the correlation with the event's period is even - * more loose: - * - * With retired taken branch: - * Effective P = P + 16 + X - * With any other event: - * Effective P = P + Y + X - * - * Where X is the number of taken branches due to interrupt - * skid. Skid is large. - * - * Where Y is the occurences of the event while BRS is - * capturing the lbr_nr entries. - * - * By using retired taken branches, we limit the impact on the - * Y variable. We know it cannot be more than the depth of - * BRS. - */ - if (!amd_is_brs_event(event)) - return -EINVAL; + if (has_branch_stack(event)) + return amd_brs_hw_config(event); - /* - * BRS implementation does not work with frequency mode - * reprogramming of the period. - */ - if (event->attr.freq) - return -EINVAL; - /* - * The kernel subtracts BRS depth from period, so it must - * be big enough. - */ - if (event->attr.sample_period <= x86_pmu.lbr_nr) - return -EINVAL; - - /* - * Check if we can allow PERF_SAMPLE_BRANCH_STACK - */ - ret = amd_brs_setup_filter(event); - - /* only set in case of success */ - if (!ret) - event->hw.flags |= PERF_X86_EVENT_AMD_BRS; - } - return ret; + return 0; } static inline int amd_is_nb_event(struct hw_perf_event *hwc) diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index ba3d24a6a4ec..5deb34e42bbd 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1233,6 +1233,9 @@ static inline bool fixed_counter_disabled(int i, struct pmu *pmu) int amd_pmu_init(void); #ifdef CONFIG_PERF_EVENTS_AMD_BRS + +#define AMD_FAM19H_BRS_EVENT 0xc4 /* RETIRED_TAKEN_BRANCH_INSTRUCTIONS */ + int amd_brs_init(void); void amd_brs_disable(void); void amd_brs_enable(void); @@ -1241,7 +1244,7 @@ void amd_brs_disable_all(void); void amd_brs_drain(void); void amd_brs_lopwr_init(void); void amd_brs_disable_all(void); -int amd_brs_setup_filter(struct perf_event *event); +int amd_brs_hw_config(struct perf_event *event); void amd_brs_reset(void); static inline void amd_pmu_brs_add(struct perf_event *event) @@ -1277,7 +1280,7 @@ static inline void amd_brs_enable(void) {} static inline void amd_brs_drain(void) {} static inline void amd_brs_lopwr_init(void) {} static inline void amd_brs_disable_all(void) {} -static inline int amd_brs_setup_filter(struct perf_event *event) +static inline int amd_brs_hw_config(struct perf_event *event) { return 0; } |