diff options
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 16e46ee42573..a7b535c265e1 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -197,6 +197,9 @@ struct request { /* for bidi */ struct request *next_rq; + + ktime_t lat_hist_io_start; + int lat_hist_enabled; }; static inline bool blk_rq_is_passthrough(struct request *rq) @@ -1683,6 +1686,62 @@ extern int bdev_write_page(struct block_device *, sector_t, struct page *, struct writeback_control *); extern long bdev_direct_access(struct block_device *, sector_t, void __pmem **addr, unsigned long *pfn, long size); + +/* + * X-axis for IO latency histogram support. + */ +static const u_int64_t latency_x_axis_us[] = { + 100, + 200, + 300, + 400, + 500, + 600, + 700, + 800, + 900, + 1000, + 1200, + 1400, + 1600, + 1800, + 2000, + 2500, + 3000, + 4000, + 5000, + 6000, + 7000, + 9000, + 10000 +}; + +#define BLK_IO_LAT_HIST_DISABLE 0 +#define BLK_IO_LAT_HIST_ENABLE 1 +#define BLK_IO_LAT_HIST_ZERO 2 + +struct io_latency_state { + u_int64_t latency_y_axis[ARRAY_SIZE(latency_x_axis_us) + 1]; + u_int64_t latency_elems; + u_int64_t latency_sum; +}; + +static inline void +blk_update_latency_hist(struct io_latency_state *s, u_int64_t delta_us) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(latency_x_axis_us); i++) + if (delta_us < (u_int64_t)latency_x_axis_us[i]) + break; + s->latency_y_axis[i]++; + s->latency_elems++; + s->latency_sum += delta_us; +} + +ssize_t blk_latency_hist_show(char* name, struct io_latency_state *s, + char *buf, int buf_size); + #else /* CONFIG_BLOCK */ struct block_device; |