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)?
Thank You
Kurtis Dorsey
Storage Performance Software Developer
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