Commit ab608344 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

perf, x86: Improve the PEBS ABI

Rename perf_event_attr::precise to perf_event_attr::precise_ip and
widen it to 2 bits. This new field describes the required precision of
the PERF_SAMPLE_IP field:

  0 - SAMPLE_IP can have arbitrary skid
  1 - SAMPLE_IP must have constant skid
  2 - SAMPLE_IP requested to have 0 skid
  3 - SAMPLE_IP must have 0 skid

And modify the Intel PEBS code accordingly. The PEBS implementation
now supports up to precise_ip == 2, where we perform the IP fixup.

Also s/PERF_RECORD_MISC_EXACT/&_IP/ to clarify its meaning, this bit
should be set for each PERF_SAMPLE_IP field known to match the actual
instruction triggering the event.

This new scheme allows for a PEBS mode that uses the buffer for more
than a single event.
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 2b0b5c6f
...@@ -488,6 +488,21 @@ static int x86_setup_perfctr(struct perf_event *event) ...@@ -488,6 +488,21 @@ static int x86_setup_perfctr(struct perf_event *event)
static int x86_pmu_hw_config(struct perf_event *event) static int x86_pmu_hw_config(struct perf_event *event)
{ {
if (event->attr.precise_ip) {
int precise = 0;
/* Support for constant skid */
if (x86_pmu.pebs)
precise++;
/* Support for IP fixup */
if (x86_pmu.lbr_nr)
precise++;
if (event->attr.precise_ip > precise)
return -EOPNOTSUPP;
}
/* /*
* Generate PMC IRQs: * Generate PMC IRQs:
* (keep 'enabled' bit clear for now) * (keep 'enabled' bit clear for now)
...@@ -1780,7 +1795,7 @@ unsigned long perf_misc_flags(struct pt_regs *regs) ...@@ -1780,7 +1795,7 @@ unsigned long perf_misc_flags(struct pt_regs *regs)
} }
if (regs->flags & PERF_EFLAGS_EXACT) if (regs->flags & PERF_EFLAGS_EXACT)
misc |= PERF_RECORD_MISC_EXACT; misc |= PERF_RECORD_MISC_EXACT_IP;
return misc; return misc;
} }
...@@ -563,7 +563,7 @@ static void intel_pmu_disable_event(struct perf_event *event) ...@@ -563,7 +563,7 @@ static void intel_pmu_disable_event(struct perf_event *event)
x86_pmu_disable_event(event); x86_pmu_disable_event(event);
if (unlikely(event->attr.precise)) if (unlikely(event->attr.precise_ip))
intel_pmu_pebs_disable(event); intel_pmu_pebs_disable(event);
} }
...@@ -615,7 +615,7 @@ static void intel_pmu_enable_event(struct perf_event *event) ...@@ -615,7 +615,7 @@ static void intel_pmu_enable_event(struct perf_event *event)
return; return;
} }
if (unlikely(event->attr.precise)) if (unlikely(event->attr.precise_ip))
intel_pmu_pebs_enable(event); intel_pmu_pebs_enable(event);
__x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE); __x86_pmu_enable_event(hwc, ARCH_PERFMON_EVENTSEL_ENABLE);
......
...@@ -307,7 +307,7 @@ intel_pebs_constraints(struct perf_event *event) ...@@ -307,7 +307,7 @@ intel_pebs_constraints(struct perf_event *event)
{ {
struct event_constraint *c; struct event_constraint *c;
if (!event->attr.precise) if (!event->attr.precise_ip)
return NULL; return NULL;
if (x86_pmu.pebs_constraints) { if (x86_pmu.pebs_constraints) {
...@@ -330,7 +330,7 @@ static void intel_pmu_pebs_enable(struct perf_event *event) ...@@ -330,7 +330,7 @@ static void intel_pmu_pebs_enable(struct perf_event *event)
cpuc->pebs_enabled |= 1ULL << hwc->idx; cpuc->pebs_enabled |= 1ULL << hwc->idx;
WARN_ON_ONCE(cpuc->enabled); WARN_ON_ONCE(cpuc->enabled);
if (x86_pmu.intel_cap.pebs_trap) if (x86_pmu.intel_cap.pebs_trap && event->attr.precise_ip > 1)
intel_pmu_lbr_enable(event); intel_pmu_lbr_enable(event);
} }
...@@ -345,7 +345,7 @@ static void intel_pmu_pebs_disable(struct perf_event *event) ...@@ -345,7 +345,7 @@ static void intel_pmu_pebs_disable(struct perf_event *event)
hwc->config |= ARCH_PERFMON_EVENTSEL_INT; hwc->config |= ARCH_PERFMON_EVENTSEL_INT;
if (x86_pmu.intel_cap.pebs_trap) if (x86_pmu.intel_cap.pebs_trap && event->attr.precise_ip > 1)
intel_pmu_lbr_disable(event); intel_pmu_lbr_disable(event);
} }
...@@ -485,7 +485,7 @@ static void __intel_pmu_pebs_event(struct perf_event *event, ...@@ -485,7 +485,7 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
regs.bp = pebs->bp; regs.bp = pebs->bp;
regs.sp = pebs->sp; regs.sp = pebs->sp;
if (intel_pmu_pebs_fixup_ip(regs)) if (event->attr.precise_ip > 1 && intel_pmu_pebs_fixup_ip(&regs))
regs.flags |= PERF_EFLAGS_EXACT; regs.flags |= PERF_EFLAGS_EXACT;
else else
regs.flags &= ~PERF_EFLAGS_EXACT; regs.flags &= ~PERF_EFLAGS_EXACT;
...@@ -518,7 +518,7 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs) ...@@ -518,7 +518,7 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
WARN_ON_ONCE(!event); WARN_ON_ONCE(!event);
if (!event->attr.precise) if (!event->attr.precise_ip)
return; return;
n = top - at; n = top - at;
...@@ -570,7 +570,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs) ...@@ -570,7 +570,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
WARN_ON_ONCE(!event); WARN_ON_ONCE(!event);
if (!event->attr.precise) if (!event->attr.precise_ip)
continue; continue;
if (__test_and_set_bit(bit, (unsigned long *)&status)) if (__test_and_set_bit(bit, (unsigned long *)&status))
......
...@@ -203,9 +203,19 @@ struct perf_event_attr { ...@@ -203,9 +203,19 @@ struct perf_event_attr {
enable_on_exec : 1, /* next exec enables */ enable_on_exec : 1, /* next exec enables */
task : 1, /* trace fork/exit */ task : 1, /* trace fork/exit */
watermark : 1, /* wakeup_watermark */ watermark : 1, /* wakeup_watermark */
precise : 1, /* OoO invariant counter */ /*
* precise_ip:
*
* 0 - SAMPLE_IP can have arbitrary skid
* 1 - SAMPLE_IP must have constant skid
* 2 - SAMPLE_IP requested to have 0 skid
* 3 - SAMPLE_IP must have 0 skid
*
* See also PERF_RECORD_MISC_EXACT_IP
*/
precise_ip : 2, /* skid constraint */
__reserved_1 : 48; __reserved_1 : 47;
union { union {
__u32 wakeup_events; /* wakeup every n events */ __u32 wakeup_events; /* wakeup every n events */
...@@ -296,7 +306,12 @@ struct perf_event_mmap_page { ...@@ -296,7 +306,12 @@ struct perf_event_mmap_page {
#define PERF_RECORD_MISC_GUEST_KERNEL (4 << 0) #define PERF_RECORD_MISC_GUEST_KERNEL (4 << 0)
#define PERF_RECORD_MISC_GUEST_USER (5 << 0) #define PERF_RECORD_MISC_GUEST_USER (5 << 0)
#define PERF_RECORD_MISC_EXACT (1 << 14) /*
* Indicates that the content of PERF_SAMPLE_IP points to
* the actual instruction that triggered the event. See also
* perf_event_attr::precise_ip.
*/
#define PERF_RECORD_MISC_EXACT_IP (1 << 14)
/* /*
* Reserve the last bit to indicate some extended misc field * Reserve the last bit to indicate some extended misc field
*/ */
......
...@@ -1021,7 +1021,7 @@ static void event__process_sample(const event_t *self, ...@@ -1021,7 +1021,7 @@ static void event__process_sample(const event_t *self,
return; return;
} }
if (self->header.misc & PERF_RECORD_MISC_EXACT) if (self->header.misc & PERF_RECORD_MISC_EXACT_IP)
exact_samples++; exact_samples++;
if (event__preprocess_sample(self, session, &al, symbol_filter) < 0 || if (event__preprocess_sample(self, session, &al, symbol_filter) < 0 ||
......
...@@ -654,10 +654,6 @@ parse_raw_event(const char **strp, struct perf_event_attr *attr) ...@@ -654,10 +654,6 @@ parse_raw_event(const char **strp, struct perf_event_attr *attr)
return EVT_FAILED; return EVT_FAILED;
n = hex2u64(str + 1, &config); n = hex2u64(str + 1, &config);
if (n > 0) { if (n > 0) {
if (str[n+1] == 'p') {
attr->precise = 1;
n++;
}
*strp = str + n + 1; *strp = str + n + 1;
attr->type = PERF_TYPE_RAW; attr->type = PERF_TYPE_RAW;
attr->config = config; attr->config = config;
...@@ -692,19 +688,29 @@ static enum event_result ...@@ -692,19 +688,29 @@ static enum event_result
parse_event_modifier(const char **strp, struct perf_event_attr *attr) parse_event_modifier(const char **strp, struct perf_event_attr *attr)
{ {
const char *str = *strp; const char *str = *strp;
int eu = 1, ek = 1, eh = 1; int exclude = 0;
int eu = 0, ek = 0, eh = 0, precise = 0;
if (*str++ != ':') if (*str++ != ':')
return 0; return 0;
while (*str) { while (*str) {
if (*str == 'u') if (*str == 'u') {
if (!exclude)
exclude = eu = ek = eh = 1;
eu = 0; eu = 0;
else if (*str == 'k') } else if (*str == 'k') {
if (!exclude)
exclude = eu = ek = eh = 1;
ek = 0; ek = 0;
else if (*str == 'h') } else if (*str == 'h') {
if (!exclude)
exclude = eu = ek = eh = 1;
eh = 0; eh = 0;
else } else if (*str == 'p') {
precise++;
} else
break; break;
++str; ++str;
} }
if (str >= *strp + 2) { if (str >= *strp + 2) {
...@@ -712,6 +718,7 @@ parse_event_modifier(const char **strp, struct perf_event_attr *attr) ...@@ -712,6 +718,7 @@ parse_event_modifier(const char **strp, struct perf_event_attr *attr)
attr->exclude_user = eu; attr->exclude_user = eu;
attr->exclude_kernel = ek; attr->exclude_kernel = ek;
attr->exclude_hv = eh; attr->exclude_hv = eh;
attr->precise_ip = precise;
return 1; return 1;
} }
return 0; return 0;
......
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