Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH v5] f2fs: introduce periodic iostat io latency traces | From | Chao Yu <> | Date | Sat, 21 Aug 2021 07:16:17 +0800 |
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On 2021/8/21 6:29, Daeho Jeong wrote: > From: Daeho Jeong <daehojeong@google.com> > > 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>
Thanks,
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