lkml.org 
[lkml]   [2019]   [Sep]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [xfs] 610125ab1e: fsmark.app_overhead -71.2% improvement
On Mon, Sep 09, 2019 at 02:06:54PM +0800, Rong Chen wrote:
> Hi Dave,
>
> On 9/9/19 1:32 PM, Dave Chinner wrote:
> > On Mon, Sep 09, 2019 at 09:58:49AM +0800, kernel test robot wrote:
> > > Greeting,
> > >
> > > FYI, we noticed a -71.2% improvement of fsmark.app_overhead due to commit:
> > A negative improvement? That's somewhat ambiguous...
>
> Sorry for causing the misunderstanding, it's a improvement not a regression.
>
>
> >
> > > 0e822255f95db400 610125ab1e4b1b48dcffe74d9d8
> > > ---------------- ---------------------------
> > > %stddev %change %stddev
> > > \ | \
> > > 1.095e+08 -71.2% 31557568 fsmark.app_overhead
> > > 6157 +95.5% 12034 fsmark.files_per_sec
> > So, the files/s rate doubled, and the amount of time spent in
> > userspace by the fsmark app dropped by 70%.
> >
> > > 167.31 -47.3% 88.25 fsmark.time.elapsed_time
> > > 167.31 -47.3% 88.25 fsmark.time.elapsed_time.max
> > Wall time went down by 50%.
> >
> > > 91.00 -8.8% 83.00 fsmark.time.percent_of_cpu_this_job_got
> > > 148.15 -53.2% 69.38 fsmark.time.system_time
> > As did system CPU.
> >
> > IOWs, this change has changed create performance by a factor of 4 -
> > the file create is 2x faster for half the CPU spent.
> >
> > I don't think this is a negative improvement - it's a large positive
> > improvement. I suspect that you need to change the metric
> > classifications for this workload...
> To avoid misunderstanding, we'll use fsmark.files_per_sec instead of
> fsmark.app_overhead in the subject.

Well, the two are separate ways of measuring improvement. A change
in one without a change in the other is just as significant as
a change in both...

Cheers,

Dave.
--
Dave Chinner
dchinner@redhat.com

\
 
 \ /
  Last update: 2019-09-09 08:21    [W:0.058 / U:2.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site