Re: [writeback] 6903673566d: +2.5% fileio.requests_per_sec

From: Fengguang Wu
Date: Fri Apr 11 2014 - 01:12:38 EST


On Thu, Apr 10, 2014 at 09:27:51PM +0200, Jan Kara wrote:
> On Thu 10-04-14 21:05:52, Wu Fengguang wrote:
> > On Thu, Apr 10, 2014 at 08:41:37PM +0800, Fengguang Wu wrote:
> > Here are the changed stats before/after the patchset:
> Thanks for gathering the numbers!
>
> > v3.14-rc8 ea87e2e7e0905325c58cf5643
> > --------------- -------------------------
> > 58.98 ~102% -73.2% 15.78 snb-drag/sysbench/fileio/600s-100%-1HDD-ext4-64G-1024-rndwr-sync
> > 2215.64 ~61% -69.2% 682.57 snb-drag/sysbench/fileio/600s-100%-1HDD-ext4-64G-1024-seqrewr-sync
> > 185.22 ~132% -93.6% 11.80 snb-drag/sysbench/fileio/600s-100%-1HDD-xfs-64G-1024-rndwr-sync
> > 2459.84 ~67% -71.1% 710.15 TOTAL fileio.request_latency_max_ms
> >
> > v3.14-rc8 ea87e2e7e0905325c58cf5643
> > --------------- -------------------------
> > 6251 ~ 0% +4.0% 6503 snb-drag/sysbench/fileio/600s-100%-1HDD-ext4-64G-1024-seqrewr-sync
> > 6532 ~ 0% +3.2% 6737 ~ 0% snb-drag/sysbench/fileio/600s-100%-1HDD-xfs-64G-1024-seqrewr-sync
> > 6444 ~ 0% +1.7% 6554 ~ 0% snb-drag/sysbench/fileio/600s-100%-1HDD-xfs-64G-1024-seqwr-sync
> > 19227 ~ 0% +3.0% 19795 TOTAL fileio.requests_per_sec
> >
> So fileio got better latency and higher requests per second. That's good.
> ...
>
> > v3.14-rc8 ea87e2e7e0905325c58cf5643
> > --------------- -------------------------
> > 397285 ~ 0% -6.9% 369872 ~ 0% lkp-st02/micro/dd-write/11HDD-RAID5-cfq-xfs-10dd
> > 359312 ~ 0% -5.5% 339685 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-xfs-100dd
> > 404981 ~ 0% -4.5% 386775 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-xfs-10dd
> > 1161579 ~ 0% -5.6% 1096334 TOTAL iostat.md0.wkB/s
> So dd writing tests got lower throughput reported by iostat. I'll try to
> have a look whether I can reproduce that. BTW: Does that also correspond to
> longer time-to-completion of the dd test?

Nope, there are no noticeable changes for time.elapsed_time:

v3.14-rc8 ea87e2e7e0905325c58cf5643
--------------- -------------------------
601.99 ~ 0% +0.0% 602.07 ~ 0% lkp-st02/micro/dd-write/11HDD-RAID5-cfq-xfs-10dd
630.92 ~ 0% -0.9% 625.24 lkp-ws02/micro/dd-write/11HDD-JBOD-cfq-ext4-100dd
615.98 ~ 0% -0.2% 614.74 lkp-ws02/micro/dd-write/11HDD-JBOD-cfq-ext4-10dd
610.58 ~ 0% -0.1% 609.92 ~ 0% lkp-ws02/micro/dd-write/11HDD-JBOD-cfq-ext4-1dd
608.90 ~ 0% +0.0% 609.09 lkp-ws02/micro/dd-write/11HDD-JBOD-cfq-xfs-100dd
604.46 ~ 0% +0.0% 604.66 lkp-ws02/micro/dd-write/11HDD-JBOD-cfq-xfs-10dd
603.67 ~ 0% +0.0% 603.70 lkp-ws02/micro/dd-write/11HDD-JBOD-cfq-xfs-1dd
606.65 ~ 0% +0.0% 606.93 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-ext4-100dd
606.31 ~ 0% +0.0% 606.49 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-ext4-10dd
602.97 ~ 0% -0.2% 601.89 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-ext4-1dd
603.92 ~ 0% -0.2% 603.01 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-xfs-100dd
602.66 ~ 0% -0.0% 602.63 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-xfs-10dd
602.19 ~ 0% +0.2% 603.52 lkp-ws02/micro/dd-write/11HDD-RAID5-cfq-xfs-1dd

>
> > v3.14-rc8 ea87e2e7e0905325c58cf5643
> > --------------- -------------------------
> > 1.2e+08 ~ 0% +4.0% 1.249e+08 snb-drag/sysbench/fileio/600s-100%-1HDD-ext4-64G-1024-seqrewr-sync
> > 1.254e+08 ~ 0% +3.1% 1.294e+08 ~ 0% snb-drag/sysbench/fileio/600s-100%-1HDD-xfs-64G-1024-seqrewr-sync
> > 1.237e+08 ~ 0% +1.7% 1.259e+08 ~ 0% snb-drag/sysbench/fileio/600s-100%-1HDD-xfs-64G-1024-seqwr-sync
> > 3.692e+08 ~ 0% +3.0% 3.801e+08 TOTAL time.file_system_outputs
> What's this measuring?

It corresponds to the "File system outputs" line in the below output.
It should be the number of dirtied pages.

% /usr/bin/time -v sleep 1
Command being timed: "sleep 1"
User time (seconds): 0.00
System time (seconds): 0.00
Percent of CPU this job got: 0%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:01.00
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 2608
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 213
Voluntary context switches: 2
Involuntary context switches: 1
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0

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