Re: runtime and status-interval

[John OCallaghan <john.ocallaghan@s3group.com>]

FYI I found the problem in fio/backend.c. Seems to be working fine now.


The fix I put together is this:

		if (td_read(td) && td->io_bytes[DDIR_READ]) {
			elapsed = utime_since_now(&td->start);
			td->ts.runtime[DDIR_READ] += elapsed/1000;
		}
		if (td_write(td) && td->io_bytes[DDIR_WRITE]) {
			elapsed = utime_since_now(&td->start);
			td->ts.runtime[DDIR_WRITE] += elapsed/1000;
		}
		if (td_trim(td) && td->io_bytes[DDIR_TRIM]) {
			elapsed = utime_since_now(&td->start);
			td->ts.runtime[DDIR_TRIM] += elapsed/1000;
		}


The problem is is that runtime is holding milliseconds but
utime_since_now() returns microseconds. I added the "/1000" to make the
conversion.

My change is a simple fix but quite possibly there are other places
within fio making the same mistake?


J




On 14/08/14 13:25, John OCallaghan wrote:
> 
> 
> Hi
> 
> I am running the fio2.1.11 and am seeing something odd with the "runt"
> value on jobs.
> 
> If I run a test with "--status-interval=5" and let it run for over 20
> seconds I see the runt go from sensible values to nonsensical values
> once it reaches the 20 second boundary.
> 
> Below is a snip from a log that I took. Notice that at the 19 second
> boundary the runt is OK (19925msec). But at the next status interval the
> runt has grown from 19 seconds to 21009 seconds!
> 
> This throws out the bw calcs (1505KB/s down to 1900B/s).
> 
> Here is my fio config file
> [global]
> time_based=1
> runtime=180
> directory=.
> size=64m
> 
> [job1-HD-ReadWrite]
> rw=readwrite
> blocksize=1500k
> filename=HDRW.STR
> rate=1500k,1500k
> 
> And I run as follows:
> 
> ./fio --status-interval=5 test.fio
> 
> 
> Hope thats useful to someone!
> John
> 
> ----------------------
> 
> job1-HD-ReadWrite: (groupid=0, jobs=1): err= 0: pid=25640: Thu Aug 14
> 13:13:20 2014
>   Description  : [HD Seq read/write]
>   read : io=30000KB, bw=1505.7KB/s, iops=1, runt= 19925msec
>     clat (msec): min=4, max=9, avg= 7.80, stdev= 1.24
>      lat (msec): min=4, max=9, avg= 7.80, stdev= 1.24
> <snip>
>     bw (KB  /s): min= 1495, max= 2991, per=100.00%, avg=1871.37,
> stdev=664.94
>   write: io=30000KB, bw=1505.7KB/s, iops=1, runt= 19925msec
>     clat (usec): min=553, max=2030, avg=1498.71, stdev=449.27
>      lat (usec): min=658, max=2161, avg=1617.00, stdev=464.46
>     clat percentiles (usec):
> <snip>
>     bw (KB  /s): min= 1488, max= 3024, per=100.00%, avg=1857.12,
> stdev=665.91
>     lat (usec) : 750=4.88%, 1000=4.88%
>     lat (msec) : 2=34.15%, 4=7.32%, 10=48.78%
> <snip>
> job1-HD-ReadWrite: (groupid=0, jobs=1): err= 0: pid=25640: Thu Aug 14
> 13:13:25 2014
>   Description  : [HD Seq read/write]
>   read : io=39000KB, bw=1900B/s, iops=0, runt=21009984msec
>     clat (msec): min=4, max=78, avg=10.49, stdev=13.99
>      lat (msec): min=4, max=78, avg=10.49, stdev=13.99
> <snip>
>     bw (KB  /s): min= 1495, max= 2991, per=100.00%, avg=1853.76,
> stdev=649.04
>   write: io=37500KB, bw=1827B/s, iops=0, runt=21009984msec
>     clat (usec): min=553, max=2030, avg=1405.73, stdev=462.04
>      lat (usec): min=610, max=2161, avg=1519.96, stdev=480.39
> <snip>
>     bw (KB  /s): min= 1488, max= 3024, per=100.00%, avg=1860.43,
> stdev=662.42
>     lat (usec) : 750=5.77%, 1000=5.77%
>     lat (msec) : 2=32.69%, 4=5.77%, 10=48.08%, 100=1.92%
>   cpu          : usr=0.02%, sys=0.34%, ctx=172, majf=0, minf=32
>   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=26/w=26/d=0, short=r=0/w=0/d=0
>      latency   : target=0, window=0, percentile=100.00%, depth=1
> 
> Run status group 0 (all jobs):
>    READ: io=39000KB, aggrb=1KB/s, minb=1KB/s, maxb=1KB/s,
> mint=21009984msec, maxt=21009984msec
>   WRITE: io=37500KB, aggrb=1KB/s, minb=1KB/s, maxb=1KB/s,
> mint=21009984msec, maxt=21009984msec
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