diff options
| -rw-r--r-- | Documentation/admin-guide/iostats.rst | 5 | ||||
| -rw-r--r-- | block/bio.c | 8 | ||||
| -rw-r--r-- | block/blk-core.c | 4 | ||||
| -rw-r--r-- | include/linux/genhd.h | 2 |
4 files changed, 11 insertions, 8 deletions
diff --git a/Documentation/admin-guide/iostats.rst b/Documentation/admin-guide/iostats.rst index df5b8345c41d..9b14b0c2c9c4 100644 --- a/Documentation/admin-guide/iostats.rst +++ b/Documentation/admin-guide/iostats.rst @@ -100,7 +100,7 @@ Field 10 -- # of milliseconds spent doing I/Os (unsigned int) Since 5.0 this field counts jiffies when at least one request was started or completed. If request runs more than 2 jiffies then some - I/O time will not be accounted unless there are other requests. + I/O time might be not accounted in case of concurrent requests. Field 11 -- weighted # of milliseconds spent doing I/Os (unsigned int) This field is incremented at each I/O start, I/O completion, I/O @@ -143,6 +143,9 @@ are summed (possibly overflowing the unsigned long variable they are summed to) and the result given to the user. There is no convenient user interface for accessing the per-CPU counters themselves. +Since 4.19 request times are measured with nanoseconds precision and +truncated to milliseconds before showing in this interface. + Disks vs Partitions ------------------- diff --git a/block/bio.c b/block/bio.c index 209715765a7a..68f65ef2ceba 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1768,14 +1768,14 @@ defer: schedule_work(&bio_dirty_work); } -void update_io_ticks(struct hd_struct *part, unsigned long now) +void update_io_ticks(struct hd_struct *part, unsigned long now, bool end) { unsigned long stamp; again: stamp = READ_ONCE(part->stamp); if (unlikely(stamp != now)) { if (likely(cmpxchg(&part->stamp, stamp, now) == stamp)) { - __part_stat_add(part, io_ticks, 1); + __part_stat_add(part, io_ticks, end ? now - stamp : 1); } } if (part->partno) { @@ -1791,7 +1791,7 @@ void generic_start_io_acct(struct request_queue *q, int op, part_stat_lock(); - update_io_ticks(part, jiffies); + update_io_ticks(part, jiffies, false); part_stat_inc(part, ios[sgrp]); part_stat_add(part, sectors[sgrp], sectors); part_inc_in_flight(q, part, op_is_write(op)); @@ -1809,7 +1809,7 @@ void generic_end_io_acct(struct request_queue *q, int req_op, part_stat_lock(); - update_io_ticks(part, now); + update_io_ticks(part, now, true); part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration)); part_stat_add(part, time_in_queue, duration); part_dec_in_flight(q, part, op_is_write(req_op)); diff --git a/block/blk-core.c b/block/blk-core.c index abfdcf81a228..4401b30a1751 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1337,7 +1337,7 @@ void blk_account_io_done(struct request *req, u64 now) part_stat_lock(); part = req->part; - update_io_ticks(part, jiffies); + update_io_ticks(part, jiffies, true); part_stat_inc(part, ios[sgrp]); part_stat_add(part, nsecs[sgrp], now - req->start_time_ns); part_stat_add(part, time_in_queue, nsecs_to_jiffies64(now - req->start_time_ns)); @@ -1379,7 +1379,7 @@ void blk_account_io_start(struct request *rq, bool new_io) rq->part = part; } - update_io_ticks(part, jiffies); + update_io_ticks(part, jiffies, false); part_stat_unlock(); } diff --git a/include/linux/genhd.h b/include/linux/genhd.h index da62b44b15be..13bb51f37b3f 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -422,7 +422,7 @@ void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw); -void update_io_ticks(struct hd_struct *part, unsigned long now); +void update_io_ticks(struct hd_struct *part, unsigned long now, bool end); /* block/genhd.c */ extern void device_add_disk(struct device *parent, struct gendisk *disk, |