Hi Sitsofe,
Thanks for your explain.
I found that if latency_target is specified, latency_window must be
along with latency_target option.
If not, fio will exit immediately.
Why the case is like that?
Thanks
Larry
On 04/11/2018 03:59 PM, Sitsofe Wheeler wrote:
Hi,
On 11 April 2018 at 07:48, Larry Chen <lchen@xxxxxxxx> wrote:
I referred to the docs and examples but I'm still hard to understand how to
use latency_target, latency_window and latency_percentile.
Could any one help explain it in detail?
Thanks in advance
Sorry for that this letter might be resent to the list because my
misoperation of subscribing fio mail list.
These options are used to probe the highest iodepth usable such that
the I/Os still have a latency equal to or below that of latency_target
on the basis that more asynchronous I/Os being sent at the same time
the higher each I/Os latency will be (this is what
http://fio.readthedocs.io/en/latest/fio_man.html#cmdoption-arg-latency-window
is trying to say). latency_window controls the time window that I/Os
are considered over. latency_percentile is used to adjust the
sensitivity to outlier I/Os during this process so a single moment
high spike is ignored.
Any clearer?
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