On Thu, 18 Nov 2021 14:27:29 +0900, Damien Le Moal wrote:
> When iops, latency, or bw logging options are used, fio will by default
> log information for any I/O that completes. The initial number of I/O
> log entries is 1024, as defined by (DEF_LOG_ENTRIES). When all log
> entries are used, new log entries are dynamically allocated by
> get_new_log(). This dynamic log entry allocation can negatively impact
> time-related statistics such as the I/O tail latencies (e.g. 99.9
> percentile completion latency) as growing the logs causes a temporary
> I/O stall (IO quiesce), which disturbs the workload steady state. The
> effect of this is especially noticeable with workloads using IO
> priorities: the tail latencies of high priority I/Os increase if the
> IO log needs to be grown.
>
> [...]
Applied, thanks!
[1/1] fio: Introduce the log_entries option
commit: 0a852a50c315776de0b43185e30576f15a420a24
Best regards,
--
Jens Axboe
