Re: poor random read nfs client results using fio on v4.1.x

[William Dauchy <william@gandi.net>]

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On Feb19 16:31, William Dauchy wrote:
> I would expect at least the same performances in v4.1.x.
> What can I do to help debug this issue?

I overlooked my config in 4.1.x and find out KASAN and kmemleak were
enabled.
however I can't reach the results I had on 3.14.x without these debug
options.

see my updated results on 4.1.x:

random-read: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=1
fio-2.1.11
Starting 1 process
Jobs: 1 (f=1): [r(1)] [100.0% done] [7136KB/0KB/0KB /s] [1784/0/0 iops] [eta 00m:00s]
random-read: (groupid=0, jobs=1): err= 0: pid=3519: Sat Feb 20 15:44:10 2016
  read : io=131072KB, bw=7617.9KB/s, iops=1904, runt= 17206msec
    clat (usec): min=281, max=2091, avg=517.56, stdev=79.68
     lat (usec): min=281, max=2092, avg=517.90, stdev=79.69
    clat percentiles (usec):
     |  1.00th=[  318],  5.00th=[  402], 10.00th=[  422], 20.00th=[  442],
     | 30.00th=[  490], 40.00th=[  506], 50.00th=[  516], 60.00th=[  524],
     | 70.00th=[  548], 80.00th=[  580], 90.00th=[  612], 95.00th=[  652],
     | 99.00th=[  716], 99.50th=[  740], 99.90th=[  772], 99.95th=[ 1208],
     | 99.99th=[ 1624]
    bw (KB  /s): min= 7080, max= 8128, per=100.00%, avg=7627.53, stdev=343.98
    lat (usec) : 500=37.34%, 750=62.32%, 1000=0.28%
    lat (msec) : 2=0.05%, 4=0.01%
  cpu          : usr=2.05%, sys=14.02%, ctx=65541, majf=0, minf=45
  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=32768/w=0/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=131072KB, aggrb=7617KB/s, minb=7617KB/s, maxb=7617KB/s, mint=17206msec, maxt=17206msec


summary:
3.14: 9348KB/s
4.1:  7617KB/s

-- 
William

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