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From: Jens Axboe <axboe@kernel.dk>
To: "Deyoung Hong (dhong)" <dhong@micron.com>,
	"fio@vger.kernel.org" <fio@vger.kernel.org>
Subject: Re: Bug using ramp_time shows cpu over 100%
Date: Tue, 8 Dec 2015 19:50:04 -0700	[thread overview]
Message-ID: <566796DC.2040308@kernel.dk> (raw)
In-Reply-To: <3ccceea7625d474b8afd2a6f6a7ab0ef@BOWEX36-B.micron.com>

On 12/08/2015 02:45 PM, Deyoung Hong (dhong) wrote:
> I saw the response on http://www.spinics.net/lists/fio/msg04392.html (didn't get the email), so I'm pasting it here.
>
> I git pulled the latest fio code and observed the specified changes.  I compiled and ran the latest code but still seeing the same problem:
>
> ===============
> test: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=libaio, iodepth=1
> fio-2.2.12-50-g5261
> Starting 1 thread
>
> test: (groupid=0, jobs=1): err= 0: pid=10726: Tue Dec  8 13:40:21 2015
>    read : io=799740KB, bw=79966KB/s, iops=19991, runt= 10001msec
>      slat (usec): min=0, max=11, avg= 0.10, stdev= 0.30
>      clat (usec): min=26, max=2624, avg=49.03, stdev=34.07
>       lat (usec): min=35, max=2624, avg=49.12, stdev=34.07
>      clat percentiles (usec):
>       |  1.00th=[   36],  5.00th=[   36], 10.00th=[   36], 20.00th=[   37],
>       | 30.00th=[   37], 40.00th=[   38], 50.00th=[   38], 60.00th=[   39],
>       | 70.00th=[   40], 80.00th=[   70], 90.00th=[   79], 95.00th=[   87],
>       | 99.00th=[   92], 99.50th=[   94], 99.90th=[  225], 99.95th=[  298],
>       | 99.99th=[ 2128]
>      bw (KB  /s): min=    0, max=81072, per=95.01%, avg=75974.80, stdev=17896.56
>      lat (usec) : 50=71.32%, 100=28.42%, 250=0.19%, 500=0.04%, 750=0.01%
>      lat (usec) : 1000=0.01%
>      lat (msec) : 2=0.01%, 4=0.01%
>    cpu          : usr=99.99%, sys=0.00%, ctx=8, majf=0, minf=0
>    IO depths    : 1=157.5%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
>       submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
>       complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
>       issued    : total=r=199935/w=0/d=0, short=r=0/w=0/d=0, drop=r=0/w=0/d=0
>       latency   : target=0, window=0, percentile=100.00%, depth=1
>
> Run status group 0 (all jobs):
>     READ: io=799740KB, aggrb=79966KB/s, minb=79966KB/s, maxb=79966KB/s, mint=10001msec, maxt=10001msec

This is showing 99.99% usr time, for a polled driver that doesn't seem 
crazy. Why do you think it's broken?

-- 
Jens Axboe



  reply	other threads:[~2015-12-09  2:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-08 21:45 Bug using ramp_time shows cpu over 100% Deyoung Hong (dhong)
2015-12-09  2:50 ` Jens Axboe [this message]
2015-12-09  9:56   ` Deyoung Hong (dhong)
2015-12-09 15:06     ` Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2015-11-25 19:36 Deyoung Hong (dhong)
2015-11-30 21:45 ` Jens Axboe

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