Hi Felix -
It might be helpful to share your job file or fio command line. Not
sure, I'm a neophyte as well with many questions such as what happens
when the number of jobs is less than the iodepth.
On 4/3/24 00:35, Felix Rubio wrote:
Hi everybody,
I have started recently to use fio, and I am getting the following
output for sequential writes:
write_throughput_i: (groupid=0, jobs=16): err= 0: pid=2301660: Tue Apr 2
21:03:41 2024
write: IOPS=2, BW=5613KiB/s (5748kB/s)(2048MiB/373607msec); 0 zone
resets
slat (msec): min=41549, max=373605, avg=260175.71, stdev=76630.63
clat (nsec): min=17445, max=31004, avg=20350.31, stdev=3744.64
lat (msec): min=235566, max=373605, avg=318209.63, stdev=32743.17
clat percentiles (nsec):
| 1.00th=[17536], 5.00th=[17536], 10.00th=[17792], 20.00th=[17792],
| 30.00th=[18048], 40.00th=[18304], 50.00th=[18304], 60.00th=[18816],
| 70.00th=[21632], 80.00th=[22144], 90.00th=[27008], 95.00th=[31104],
| 99.00th=[31104], 99.50th=[31104], 99.90th=[31104], 99.95th=[31104],
| 99.99th=[31104]
bw ( MiB/s): min= 2051, max= 2051, per=100.00%, avg=2051.84, stdev=
0.00, samples=16
iops : min= 2048, max= 2048, avg=2048.00, stdev= 0.00,
samples=16
lat (usec) : 20=68.75%, 50=31.25%
cpu : usr=0.00%, sys=0.02%, ctx=8350, majf=13, minf=633
IO depths : 1=0.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%,
>=64=100.0%
submit : 0=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=100.0%,
>=64=0.0%
complete : 0=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=100.0%,
>=64=0.0%
issued rwts: total=0,1024,0,0 short=0,0,0,0 dropped=0,0,0,0
latency : target=0, window=0, percentile=100.00%, depth=64
Run status group 0 (all jobs):
WRITE: bw=5613KiB/s (5748kB/s), 5613KiB/s-5613KiB/s
(5748kB/s-5748kB/s), io=2048MiB (2147MB), run=373607-373607msec
Should I understand this correctly, the submission latency (slat) is at
minimum 41.5 seconds? I am experiencing problems with my SSD disk (the
performance is pretty low, which this seems to confirm), but now I am
wondering if this could be a problem with my OS and not my disk, being
the slat the submission latency?
Thank you
