On 2011-09-08 14:31, Kurt wrote: > Hello FIO community > > I have been working with FIO for a month or so and have studied the source code quite a bit as well. I have run into an issue where my CPU utilization (sys/user) is actually higher than 100% and in some cases it is higher than 200%!!! When my actual cpu utilization is nowhere near that. > > These tests were performed on a > Dell T610 > 1x E5520 @ 2.27GHz 4 core / 8 thread > 6GB Ram > > Example: > > [global] > direct=1 > ramp_time=15 > runtime=30 > loops=1 > sync=0 > filename=/dev/sdb > > [512_Seq_Read-256] > rw=read > bs=512 > rwmixread=100 > iodepth=256 > randrepeat=0 > ioengine=libaio > name=512_Seq_Read-256 > numjobs=2 > > 512_Seq_Read-256: (g=0): rw=read, bs=512-512/512-512, ioengine=libaio, iodepth=256 > 512_Seq_Read-256: (g=0): rw=read, bs=512-512/512-512, ioengine=libaio, iodepth=256 > fio 1.57 > Starting 2 threads > > 512_Seq_Read-256: (groupid=0, jobs=1): err= 0: pid=25402 > read : io=2107.7MB, bw=71933KB/s, iops=143857 , runt= 30003msec > slat (usec): min=1 , max=472 , avg= 3.73, stdev=11.11 > clat (usec): min=133 , max=9529 , avg=1774.29, stdev=867.16 > lat (usec): min=137 , max=9531 , avg=1778.35, stdev=868.14 > bw (KB/s) : min= 0, max=102671, per=9.42%, avg=13701.43, stdev=29175.35 > cpu : usr=135.37%, sys=132.84%, ctx=346431, majf=0, minf=302 > IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=151.0% > 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=0.1% > issued r/w/d: total=4316167/0/0, short=0/0/0 > lat (usec): 250=0.39%, 500=6.15%, 750=9.10%, 1000=8.69% > lat (msec): 2=29.94%, 4=44.97%, 10=0.76% > 512_Seq_Read-256: (groupid=0, jobs=1): err= 0: pid=25403 > read : io=2156.4MB, bw=73590KB/s, iops=147171 , runt= 30001msec > slat (usec): min=1 , max=650 , avg= 3.69, stdev=11.05 > clat (usec): min=130 , max=10959 , avg=1734.38, stdev=860.90 > lat (usec): min=133 , max=10961 , avg=1738.34, stdev=861.86 > bw (KB/s) : min= 0, max=103101, per=49.60%, avg=72180.12, stdev=18747.47 > cpu : usr=135.38%, sys=132.85%, ctx=346416, majf=0, minf=217 > IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=149.7% > 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=0.1% > issued r/w/d: total=4415302/0/0, short=0/0/0 > lat (usec): 250=0.42%, 500=6.52%, 750=9.49%, 1000=9.03% > lat (msec): 2=30.91%, 4=42.90%, 10=0.74%, 20=0.01% > > Run status group 0 (all jobs): > READ: io=4263.7MB, aggrb=145518KB/s, minb=73659KB/s, maxb=75356KB/s, mint=30001msec, maxt=30003msec > > Disk stats (read/write): > sdb: ios=3980775/0, merge=9097849/0, ticks=4798475/0, in_queue=4798485, util=99.98% > > As you see the CPU is 135% both usr and sys… do I need to divide by the number of processor threads (8)? I suspect you didn't copy the job file correctly, as it has no mention of 'thread' but you are indeed using threads and not processes. The usr/sys are accumulated for all threads in a group, so that is why it could in theory be nr_threads * 100% for both usr and sys time. So yes, if you wish to inspect per-thread usage, divide by the number of jobs that you are running. In your case that would be 2. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
