Created
February 2, 2013 02:52
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fio test
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2 problems: | |
1. ignores runtime | |
2. doesn't output actual measurements (other than issued total) | |
[~/fio-2.0.13]# time ./fio --name=randread --rw=randread --random_distribution=pareto:0.5 --size=1g --bs=8k --runtime=10 --time_based --filename=fio.tmp | |
randread: (g=0): rw=randread, bs=8K-8K/8K-8K/8K-8K, ioengine=sync, iodepth=1 | |
fio-2.0.13 | |
Starting 1 process | |
^C | |
fio: terminating on signal 2 | |
randread: (groupid=0, jobs=1): err= 0: pid=18537: Sat Feb 2 02:50:03 2013 | |
lat (usec) : 2=100.00% | |
cpu : usr=0.00%, sys=0.00%, ctx=4776, majf=0, minf=0 | |
IO depths : 1=100.0%, 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=2274693/w=0/d=0, short=r=0/w=0/d=0 | |
Run status group 0 (all jobs): | |
real 0m28.465s | |
user 0m5.731s | |
sys 0m20.696s |
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latest version of fio (git://git.kernel.dk/fio.git) fixed many problems; --clocksource=clock_gettime fixed the runtime.
Note that this does mean a high rate of gettime calls:
Although, the CPU cost is only about 10% for this particular workload (8k random read cached), so, not as bad as the syscall count would suggest:
It's spending most of its CPU time in read(), which is good. Numbers are nanosecond sums of CPU time during syscalls. YMMV. I should also sample this as well (other than tracing) to double check.