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From: Felix Rubio <felix@kngnt.org>
To: fio@vger.kernel.org
Subject: help understanding the output of fio
Date: Wed, 03 Apr 2024 07:35:52 +0200	[thread overview]
Message-ID: <90e42eaab7569a03239ad05dfd1ebb1d@kngnt.org> (raw)

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
-- 
Felix Rubio
"Don't believe what you're told. Double check."
Felix Rubio

             reply	other threads:[~2024-04-03  5:35 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-03  5:35 Felix Rubio [this message]
2024-04-03 15:45 ` help understanding the output of fio Patrick Goetz
2024-04-03 19:21   ` Felix Rubio
2024-04-04  4:28     ` Damien Le Moal
2024-04-04 16:18       ` Patrick Goetz
2024-04-04 23:37         ` Damien Le Moal
     [not found]       ` <4d12ea060363d934d84201f834b21a38@kngnt.org>
     [not found]         ` <e9efa7bb-f2b3-47f0-aa03-5191f85562e8@kernel.org>
2024-04-04 18:29           ` Felix Rubio
2024-04-04 18:43       ` Jeff Johnson
2024-04-04 18:59         ` Felix Rubio
2024-04-04 19:07           ` Jeff Johnson
2024-04-05  5:41             ` Felix Rubio
2024-04-05 18:39               ` Jeff Johnson
2024-04-06  7:03                 ` Felix Rubio

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