diff options
| -rw-r--r-- | Documentation/device-mapper/statistics.txt | 19 | ||||
| -rw-r--r-- | drivers/md/dm-stats.c | 205 |
2 files changed, 199 insertions, 25 deletions
diff --git a/Documentation/device-mapper/statistics.txt b/Documentation/device-mapper/statistics.txt index ff6baeaa71f7..4919b2dfd1b3 100644 --- a/Documentation/device-mapper/statistics.txt +++ b/Documentation/device-mapper/statistics.txt @@ -13,9 +13,10 @@ the range specified. The I/O statistics counters for each step-sized area of a region are in the same format as /sys/block/*/stat or /proc/diskstats (see: Documentation/iostats.txt). But two extra counters (12 and 13) are -provided: total time spent reading and writing. All these counters may -be accessed by sending the @stats_print message to the appropriate DM -device via dmsetup. +provided: total time spent reading and writing. When the histogram +argument is used, the 14th parameter is reported that represents the +histogram of latencies. All these counters may be accessed by sending +the @stats_print message to the appropriate DM device via dmsetup. The reported times are in milliseconds and the granularity depends on the kernel ticks. When the option precise_timestamps is used, the @@ -64,6 +65,18 @@ Messages used, the resulting times are in nanoseconds instead of milliseconds. Precise timestamps are a little bit slower to obtain than jiffies-based timestamps. + histogram:n1,n2,n3,n4,... - collect histogram of latencies. The + numbers n1, n2, etc are times that represent the boundaries + of the histogram. If precise_timestamps is not used, the + times are in milliseconds, otherwise they are in + nanoseconds. For each range, the kernel will report the + number of requests that completed within this range. For + example, if we use "histogram:10,20,30", the kernel will + report four numbers a:b:c:d. a is the number of requests + that took 0-10 ms to complete, b is the number of requests + that took 10-20 ms to complete, c is the number of requests + that took 20-30 ms to complete and d is the number of + requests that took more than 30 ms to complete. <program_id> An optional parameter. A name that uniquely identifies diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c index 4bfd84ab1d4a..faf1071ef631 100644 --- a/drivers/md/dm-stats.c +++ b/drivers/md/dm-stats.c @@ -29,6 +29,7 @@ struct dm_stat_percpu { unsigned long long io_ticks[2]; unsigned long long io_ticks_total; unsigned long long time_in_queue; + unsigned long long *histogram; }; struct dm_stat_shared { @@ -45,11 +46,14 @@ struct dm_stat { sector_t start; sector_t end; sector_t step; + unsigned n_histogram_entries; + unsigned long long *histogram_boundaries; const char *program_id; const char *aux_data; struct rcu_head rcu_head; size_t shared_alloc_size; size_t percpu_alloc_size; + size_t histogram_alloc_size; struct dm_stat_percpu *stat_percpu[NR_CPUS]; struct dm_stat_shared stat_shared[0]; }; @@ -173,8 +177,11 @@ static void dm_stat_free(struct rcu_head *head) kfree(s->program_id); kfree(s->aux_data); - for_each_possible_cpu(cpu) + for_each_possible_cpu(cpu) { + dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size); dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size); + } + dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size); dm_kvfree(s, s->shared_alloc_size); } @@ -228,6 +235,8 @@ void dm_stats_cleanup(struct dm_stats *stats) static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, sector_t step, unsigned stat_flags, + unsigned n_histogram_entries, + unsigned long long *histogram_boundaries, const char *program_id, const char *aux_data, void (*suspend_callback)(struct mapped_device *), void (*resume_callback)(struct mapped_device *), @@ -239,6 +248,7 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, size_t ni; size_t shared_alloc_size; size_t percpu_alloc_size; + size_t histogram_alloc_size; struct dm_stat_percpu *p; int cpu; int ret_id; @@ -262,7 +272,12 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries) return -EOVERFLOW; - if (!check_shared_memory(shared_alloc_size + num_possible_cpus() * percpu_alloc_size)) + histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long); + if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long)) + return -EOVERFLOW; + + if (!check_shared_memory(shared_alloc_size + histogram_alloc_size + + num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size))) return -ENOMEM; s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE); @@ -276,6 +291,15 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, s->step = step; s->shared_alloc_size = shared_alloc_size; s->percpu_alloc_size = percpu_alloc_size; + s->histogram_alloc_size = histogram_alloc_size; + + s->n_histogram_entries = n_histogram_entries; + s->histogram_boundaries = kmemdup(histogram_boundaries, + s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL); + if (!s->histogram_boundaries) { + r = -ENOMEM; + goto out; + } s->program_id = kstrdup(program_id, GFP_KERNEL); if (!s->program_id) { @@ -293,6 +317,19 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0); } + if (s->n_histogram_entries) { + unsigned long long *hi; + hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE); + if (!hi) { + r = -ENOMEM; + goto out; + } + for (ni = 0; ni < n_entries; ni++) { + s->stat_shared[ni].tmp.histogram = hi; + hi += s->n_histogram_entries + 1; + } + } + for_each_possible_cpu(cpu) { p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu)); if (!p) { @@ -300,6 +337,18 @@ static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, goto out; } s->stat_percpu[cpu] = p; + if (s->n_histogram_entries) { + unsigned long long *hi; + hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu)); + if (!hi) { + r = -ENOMEM; + goto out; + } + for (ni = 0; ni < n_entries; ni++) { + p[ni].histogram = hi; + hi += s->n_histogram_entries + 1; + } + } } /* @@ -377,9 +426,11 @@ static int dm_stats_delete(struct dm_stats *stats, int id) * vfree can't be called from RCU callback */ for_each_possible_cpu(cpu) - if (is_vmalloc_addr(s->stat_percpu)) + if (is_vmalloc_addr(s->stat_percpu) || + is_vmalloc_addr(s->stat_percpu[cpu][0].histogram)) goto do_sync_free; - if (is_vmalloc_addr(s)) { + if (is_vmalloc_addr(s) || + is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) { do_sync_free: synchronize_rcu_expedited(); dm_stat_free(&s->rcu_head); @@ -486,15 +537,32 @@ static void dm_stat_for_entry(struct dm_stat *s, size_t entry, dm_stat_round(s, shared, p); atomic_inc(&shared->in_flight[idx]); } else { + unsigned long long duration; dm_stat_round(s, shared, p); atomic_dec(&shared->in_flight[idx]); p->sectors[idx] += len; p->ios[idx] += 1; p->merges[idx] += stats_aux->merged; - if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) + if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) { p->ticks[idx] += duration_jiffies; - else + duration = jiffies_to_msecs(duration_jiffies); + } else { p->ticks[idx] += stats_aux->duration_ns; + duration = stats_aux->duration_ns; + } + if (s->n_histogram_entries) { + unsigned lo = 0, hi = s->n_histogram_entries + 1; + while (lo + 1 < hi) { + unsigned mid = (lo + hi) / 2; + if (s->histogram_boundaries[mid - 1] > duration) { + hi = mid; + } else { + lo = mid; + } + + } + p->histogram[lo]++; + } } #if BITS_PER_LONG == 32 @@ -600,7 +668,22 @@ static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared dm_stat_round(s, shared, p); local_irq_enable(); - memset(&shared->tmp, 0, sizeof(shared->tmp)); + shared->tmp.sectors[READ] = 0; + shared->tmp.sectors[WRITE] = 0; + shared->tmp.ios[READ] = 0; + shared->tmp.ios[WRITE] = 0; + shared->tmp.merges[READ] = 0; + shared->tmp.merges[WRITE] = 0; + shared->tmp.ticks[READ] = 0; + shared->tmp.ticks[WRITE] = 0; + shared->tmp.io_ticks[READ] = 0; + shared->tmp.io_ticks[WRITE] = 0; + shared->tmp.io_ticks_total = 0; + shared->tmp.time_in_queue = 0; + + if (s->n_histogram_entries) + memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long)); + for_each_possible_cpu(cpu) { p = &s->stat_percpu[cpu][x]; shared->tmp.sectors[READ] += ACCESS_ONCE(p->sectors[READ]); @@ -615,6 +698,11 @@ static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]); shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total); shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue); + if (s->n_histogram_entries) { + unsigned i; + for (i = 0; i < s->n_histogram_entries + 1; i++) + shared->tmp.histogram[i] += ACCESS_ONCE(p->histogram[i]); + } } } @@ -644,6 +732,15 @@ static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end, p->io_ticks_total -= shared->tmp.io_ticks_total; p->time_in_queue -= shared->tmp.time_in_queue; local_irq_enable(); + if (s->n_histogram_entries) { + unsigned i; + for (i = 0; i < s->n_histogram_entries + 1; i++) { + local_irq_disable(); + p = &s->stat_percpu[smp_processor_id()][x]; + p->histogram[i] -= shared->tmp.histogram[i]; + local_irq_enable(); + } + } } } @@ -733,7 +830,7 @@ static int dm_stats_print(struct dm_stats *stats, int id, __dm_stat_init_temporary_percpu_totals(shared, s, x); - DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu\n", + DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu", (unsigned long long)start, (unsigned long long)step, shared->tmp.ios[READ], @@ -749,6 +846,13 @@ static int dm_stats_print(struct dm_stats *stats, int id, dm_jiffies_to_msec64(s, shared->tmp.time_in_queue), dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]), dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE])); + if (s->n_histogram_entries) { + unsigned i; + for (i = 0; i < s->n_histogram_entries + 1; i++) { + DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]); + } + } + DMEMIT("\n"); if (unlikely(sz + 1 >= maxlen)) goto buffer_overflow; @@ -790,10 +894,47 @@ static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data return 0; } +static int parse_histogram(const char *h, unsigned *n_histogram_entries, + unsigned long long **histogram_boundaries) +{ + const char *q; + unsigned n; + unsigned long long last; + + *n_histogram_entries = 1; + for (q = h; *q; q++) + if (*q == ',') + (*n_histogram_entries)++; + + *histogram_boundaries = kmalloc(*n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL); + if (!*histogram_boundaries) + return -ENOMEM; + + n = 0; + last = 0; + while (1) { + unsigned long long hi; + int s; + char ch; + s = sscanf(h, "%llu%c", &hi, &ch); + if (!s || (s == 2 && ch != ',')) + return -EINVAL; + if (hi <= last) + return -EINVAL; + last = hi; + (*histogram_boundaries)[n] = hi; + if (s == 1) + return 0; + h = strchr(h, ',') + 1; + n++; + } +} + static int message_stats_create(struct mapped_device *md, unsigned argc, char **argv, char *result, unsigned maxlen) { + int r; int id; char dummy; unsigned long long start, end, len, step; @@ -801,6 +942,9 @@ static int message_stats_create(struct mapped_device *md, const char *program_id, *aux_data; unsigned stat_flags = 0; + unsigned n_histogram_entries = 0; + unsigned long long *histogram_boundaries = NULL; + struct dm_arg_set as, as_backup; const char *a; unsigned feature_args; @@ -811,7 +955,7 @@ static int message_stats_create(struct mapped_device *md, */ if (argc < 3) - return -EINVAL; + goto ret_einval; as.argc = argc; as.argv = argv; @@ -825,11 +969,11 @@ static int message_stats_create(struct mapped_device *md, len = 1; } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 || start != (sector_t)start || len != (sector_t)len) - return -EINVAL; + goto ret_einval; end = start + len; if (start >= end) - return -EINVAL; + goto ret_einval; a = dm_shift_arg(&as); if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) { @@ -842,7 +986,7 @@ static int message_stats_create(struct mapped_device *md, step = 1; } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 || step != (sector_t)step || !step) - return -EINVAL; + goto ret_einval; as_backup = as; a = dm_shift_arg(&as); @@ -850,11 +994,16 @@ static int message_stats_create(struct mapped_device *md, while (feature_args--) { a = dm_shift_arg(&as); if (!a) - return -EINVAL; + goto ret_einval; if (!strcasecmp(a, "precise_timestamps")) stat_flags |= STAT_PRECISE_TIMESTAMPS; - else - return -EINVAL; + else if (!strncasecmp(a, "histogram:", 10)) { + if (n_histogram_entries) + goto ret_einval; + if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries))) + goto ret; + } else + goto ret_einval; } } else { as = as_backup; @@ -872,7 +1021,7 @@ static int message_stats_create(struct mapped_device *md, aux_data = a; if (as.argc) - return -EINVAL; + goto ret_einval; /* * If a buffer overflow happens after we created the region, @@ -881,17 +1030,29 @@ static int message_stats_create(struct mapped_device *md, * leaked). So we must detect buffer overflow in advance. */ snprintf(result, maxlen, "%d", INT_MAX); - if (dm_message_test_buffer_overflow(result, maxlen)) - return 1; + if (dm_message_test_buffer_overflow(result, maxlen)) { + r = 1; + goto ret; + } - id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags, program_id, aux_data, + id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags, + n_histogram_entries, histogram_boundaries, program_id, aux_data, dm_internal_suspend_fast, dm_internal_resume_fast, md); - if (id < 0) - return id; + if (id < 0) { + r = id; + goto ret; + } snprintf(result, maxlen, "%d", id); - return 1; + r = 1; + goto ret; + +ret_einval: + r = -EINVAL; +ret: + kfree(histogram_boundaries); + return r; } static int message_stats_delete(struct mapped_device *md, |