Hi,
The patchset mostly introduces some additional io stats for latency and sector,
with those tables, we can know better about the io patttern. And we want the
disk_start_io_acct returns ns instead of convert from jiffies, so some code
in drbd are changed accordingly.
For the table, the first row of below tables means the number which are "<= 1",
while the last row means the number which are ">= 1024". And the rest rows in
the table represent the number in a range.
With HZ=1000.
$ cat /sys/block/md127/io_latency
1 ms: 3 0 0 0 - means 3 read IOs are finished less than or equal 1 ms
2 ms: 1 0 0 0 - means 1 read IO is finished in the range [2ms, 4ms)
4 ms: 0 0 0 0
8 ms: 0 0 0 0
16 ms: 1 0 0 0
32 ms: 0 0 0 0
64 ms: 0 0 0 0
128 ms: 0 0 0 0
256 ms: 0 0 0 0
512 ms: 0 0 0 0
1024 ms: 1 0 0 0
2048 ms: 1 0 0 0 - means 1 read IO is finished more than or equal 2048 ms
While with HZ=100.
$ cat /sys/block/md127/io_latency
10 ms: 3 0 0 0
20 ms: 1 0 0 0
40 ms: 0 0 0 0
80 ms: 0 0 0 0
160 ms: 1 0 0 0
320 ms: 0 0 0 0
640 ms: 0 0 0 0
1280 ms: 0 0 0 0
2560 ms: 0 0 0 0
5120 ms: 0 0 0 0
10240 ms: 1 0 0 0
20480 ms: 1 0 0 0
$ cat /sys/block/md127/io_size
1 KB: 0 0 0 0
2 KB: 0 0 0 0
4 KB: 0 0 0 0
8 KB: 5 0 0 0
16 KB: 0 0 0 0
32 KB: 0 0 0 0
64 KB: 0 0 0 0
128 KB: 0 0 0 0
256 KB: 0 0 0 0
512 KB: 0 0 0 0
1024 KB: 0 0 0 0
2048 KB: 0 0 0 0
I will add a document if it is worth to add the two tables, review and comment
are welcome.
Thanks,
Guoqing
Guoqing Jiang (5):
block: return ns precision from disk_start_io_acct
drbd: remove unused argument from drbd_request_prepare and
__drbd_make_request
drbd: rename start_jif to start_ns
block: add a statistic table for io latency
block: add a statistic table for io sector
block/Kconfig | 9 +++++
block/blk-core.c | 61 +++++++++++++++++++++++++++++--
block/genhd.c | 47 ++++++++++++++++++++++++
drivers/block/drbd/drbd_debugfs.c | 8 ++--
drivers/block/drbd/drbd_int.h | 4 +-
drivers/block/drbd/drbd_main.c | 3 +-
drivers/block/drbd/drbd_req.c | 15 +++-----
include/linux/part_stat.h | 8 ++++
8 files changed, 135 insertions(+), 20 deletions(-)
