linux/include
Daeho Jeong a4b6817625 f2fs: introduce periodic iostat io latency traces
Whenever we notice some sluggish issues on our machines, we are always
curious about how well all types of I/O in the f2fs filesystem are
handled. But, it's hard to get this kind of real data. First of all,
we need to reproduce the issue while turning on the profiling tool like
blktrace, but the issue doesn't happen again easily. Second, with the
intervention of any tools, the overall timing of the issue will be
slightly changed and it sometimes makes us hard to figure it out.

So, I added the feature printing out IO latency statistics tracepoint
events, which are minimal things to understand filesystem's I/O related
behaviors, into F2FS_IOSTAT kernel config. With "iostat_enable" sysfs
node on, we can get this statistics info in a periodic way and it
would cause the least overhead.

[samples]
 f2fs_ckpt-254:1-507     [003] ....  2842.439683: f2fs_iostat_latency:
dev = (254,11), iotype [peak lat.(ms)/avg lat.(ms)/count],
rd_data [136/1/801], rd_node [136/1/1704], rd_meta [4/2/4],
wr_sync_data [164/16/3331], wr_sync_node [152/3/648],
wr_sync_meta [160/2/4243], wr_async_data [24/13/15],
wr_async_node [0/0/0], wr_async_meta [0/0/0]

 f2fs_ckpt-254:1-507     [002] ....  2845.450514: f2fs_iostat_latency:
dev = (254,11), iotype [peak lat.(ms)/avg lat.(ms)/count],
rd_data [60/3/456], rd_node [60/3/1258], rd_meta [0/0/1],
wr_sync_data [120/12/2285], wr_sync_node [88/5/428],
wr_sync_meta [52/6/2990], wr_async_data [4/1/3],
wr_async_node [0/0/0], wr_async_meta [0/0/0]

Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2021-08-23 10:25:51 -07:00
..
acpi IOMMU Updates for Linux v5.14 2021-07-02 13:22:47 -07:00
asm-generic This pull request contains the following changes for UML: 2021-07-09 10:19:13 -07:00
clocksource
crypto crypto: scatterwalk - Remove obsolete PageSlab check 2021-06-28 11:28:08 +08:00
drm
dt-bindings ARM: Drivers for 5.14 2021-07-10 09:46:20 -07:00
keys
kunit linux-kselftest-kunit-fixes-5.14-rc1 2021-07-02 12:58:26 -07:00
kvm
linux Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
math-emu
media media: Fix Media Controller API config checks 2021-06-24 14:26:00 +02:00
memory
misc
net Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-07-03 11:30:04 -07:00
pcmcia
ras
rdma
scsi SCSI misc on 20210702 2021-07-02 15:14:36 -07:00
soc ARM: Drivers for 5.14 2021-07-10 09:46:20 -07:00
sound ASoC: Updates for v5.14 2021-07-01 08:36:12 +02:00
target
trace f2fs: introduce periodic iostat io latency traces 2021-08-23 10:25:51 -07:00
uapi block-5.14-2021-07-08 2021-07-09 12:05:33 -07:00
vdso
video
xen xen: sync include/xen/interface/io/ring.h with Xen's newest version 2021-07-05 09:49:45 +02:00