diff options
Diffstat (limited to 'include/linux/perf_event.h')
| -rw-r--r-- | include/linux/perf_event.h | 90 |
1 files changed, 80 insertions, 10 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index bd9f55a5958d..ddbb6a901f65 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -299,18 +299,31 @@ struct perf_event_mmap_page { /* * Bits needed to read the hw events in user-space. * - * u32 seq; - * s64 count; + * u32 seq, time_mult, time_shift, idx, width; + * u64 count, enabled, running; + * u64 cyc, time_offset; + * s64 pmc = 0; * * do { * seq = pc->lock; - * * barrier() - * if (pc->index) { - * count = pmc_read(pc->index - 1); - * count += pc->offset; - * } else - * goto regular_read; + * + * enabled = pc->time_enabled; + * running = pc->time_running; + * + * if (pc->cap_usr_time && enabled != running) { + * cyc = rdtsc(); + * time_offset = pc->time_offset; + * time_mult = pc->time_mult; + * time_shift = pc->time_shift; + * } + * + * idx = pc->index; + * count = pc->offset; + * if (pc->cap_usr_rdpmc && idx) { + * width = pc->pmc_width; + * pmc = rdpmc(idx - 1); + * } * * barrier(); * } while (pc->lock != seq); @@ -323,14 +336,57 @@ struct perf_event_mmap_page { __s64 offset; /* add to hardware event value */ __u64 time_enabled; /* time event active */ __u64 time_running; /* time event on cpu */ - __u32 time_mult, time_shift; + union { + __u64 capabilities; + __u64 cap_usr_time : 1, + cap_usr_rdpmc : 1, + cap_____res : 62; + }; + + /* + * If cap_usr_rdpmc this field provides the bit-width of the value + * read using the rdpmc() or equivalent instruction. This can be used + * to sign extend the result like: + * + * pmc <<= 64 - width; + * pmc >>= 64 - width; // signed shift right + * count += pmc; + */ + __u16 pmc_width; + + /* + * If cap_usr_time the below fields can be used to compute the time + * delta since time_enabled (in ns) using rdtsc or similar. + * + * u64 quot, rem; + * u64 delta; + * + * quot = (cyc >> time_shift); + * rem = cyc & ((1 << time_shift) - 1); + * delta = time_offset + quot * time_mult + + * ((rem * time_mult) >> time_shift); + * + * Where time_offset,time_mult,time_shift and cyc are read in the + * seqcount loop described above. This delta can then be added to + * enabled and possible running (if idx), improving the scaling: + * + * enabled += delta; + * if (idx) + * running += delta; + * + * quot = count / running; + * rem = count % running; + * count = quot * enabled + (rem * enabled) / running; + */ + __u16 time_shift; + __u32 time_mult; __u64 time_offset; /* * Hole for extension of the self monitor capabilities */ - __u64 __reserved[121]; /* align to 1k */ + __u64 __reserved[120]; /* align to 1k */ /* * Control data for the mmap() data buffer. @@ -550,6 +606,7 @@ struct perf_guest_info_callbacks { #include <linux/irq_work.h> #include <linux/static_key.h> #include <linux/atomic.h> +#include <linux/sysfs.h> #include <asm/local.h> #define PERF_MAX_STACK_DEPTH 255 @@ -1291,5 +1348,18 @@ do { \ register_cpu_notifier(&fn##_nb); \ } while (0) + +#define PMU_FORMAT_ATTR(_name, _format) \ +static ssize_t \ +_name##_show(struct device *dev, \ + struct device_attribute *attr, \ + char *page) \ +{ \ + BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE); \ + return sprintf(page, _format "\n"); \ +} \ + \ +static struct device_attribute format_attr_##_name = __ATTR_RO(_name) + #endif /* __KERNEL__ */ #endif /* _LINUX_PERF_EVENT_H */ |