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@xxxxxxxxxx
