[pve-devel] pve-manager and disk IO monitoring

[Alexandre DERUMIER]

>>Where do you see that 11% difference? 

oh, sorry, my fault, I read the wrong line...
Jobs: 1 (f=1): [m(1)] [100.0% done] [64339KB/16908KB/0KB /s] [15.2K/3816/0 iops] [eta 00m:00s] 
Jobs: 1 (f=1): [m(1)] [100.0% done] [73928KB/19507KB/0KB /s] [17.3K/4381/0 iops] [eta 00m:00s] 

But check the latencies (>95th are twice lower) :

read
-----

block:
read : io=2454.9MB, bw=87501KB/s, iops=14328, runt= 28728msec 
clat percentiles (usec): 
| 1.00th=[ 1768], 5.00th=[ 2480], 10.00th=[ 2640], 20.00th=[ 2864], 
| 30.00th=[ 2960], 40.00th=[ 3056], 50.00th=[ 3088], 60.00th=[ 3152], 
| 70.00th=[ 3248], 80.00th=[ 3376], 90.00th=[ 3824], 95.00th=[ 4448], 
| 99.00th=[ 8768], 99.50th=[13120], 99.90th=[52992], 99.95th=[103936], 
| 99.99th=[536576] 

generic:

read : io=2454.9MB, bw=88384KB/s, iops=14473, runt= 28441msec 
slat (usec): min=5, max=5814, avg=10.86, stdev=21.71 
clat (usec): min=459, max=885935, avg=3451.71, stdev=3297.21 
lat (usec): min=526, max=885944, avg=3462.97, stdev=3297.14 
clat percentiles (msec): 
| 1.00th=[ 3], 5.00th=[ 3], 10.00th=[ 3], 20.00th=[ 4], 
| 30.00th=[ 4], 40.00th=[ 4], 50.00th=[ 4], 60.00th=[ 4], 
| 70.00th=[ 4], 80.00th=[ 4], 90.00th=[ 4], 95.00th=[ 5], 
| 99.00th=[ 8], 99.50th=[ 11], 99.90th=[ 23], 99.95th=[ 63], 
| 99.99th=[ 153] 



write
-----
block

bw (KB /s): min= 7148, max=193016, per=100.00%, avg=87866.39, stdev=28395.12 
write: io=631998KB, bw=21999KB/s, iops=3590, runt= 28728msec 
slat (usec): min=4, max=9301, avg=12.69, stdev=33.41 
clat (usec): min=299, max=778312, avg=3871.08, stdev=7378.66 
lat (usec): min=305, max=778320, avg=3884.17, stdev=7378.66 
clat percentiles (msec): 
| 1.00th=[ 3], 5.00th=[ 3], 10.00th=[ 3], 20.00th=[ 3], 
| 30.00th=[ 4], 40.00th=[ 4], 50.00th=[ 4], 60.00th=[ 4], 
| 70.00th=[ 4], 80.00th=[ 4], 90.00th=[ 5], 95.00th=[ 7], 
| 99.00th=[ 13], 99.50th=[ 19], 99.90th=[ 55], 99.95th=[ 101], 
| 99.99th=[ 537] 

generic

write: io=631998KB, bw=22221KB/s, iops=3627, runt= 28441msec 
slat (usec): min=6, max=3864, avg=12.96, stdev=24.18 
clat (usec): min=582, max=156777, avg=3801.87, stdev=3128.06 
lat (usec): min=610, max=156789, avg=3815.24, stdev=3128.36 
clat percentiles (msec): 
| 1.00th=[ 3], 5.00th=[ 3], 10.00th=[ 3], 20.00th=[ 4], 
| 30.00th=[ 4], 40.00th=[ 4], 50.00th=[ 4], 60.00th=[ 4], 
| 70.00th=[ 4], 80.00th=[ 4], 90.00th=[ 5], 95.00th=[ 7], 
| 99.00th=[ 11], 99.50th=[ 15], 99.90th=[ 49], 99.95th=[ 74], 
| 99.99th=[ 153] 
----- Mail original -----
De: "dietmar" <dietmar at proxmox.com>
À: "aderumier" <aderumier at odiso.com>, "pve-devel" <pve-devel at pve.proxmox.com>
Envoyé: Vendredi 30 Septembre 2016 07:38:43
Objet: Re: [pve-devel] pve-manager and disk IO monitoring

> On September 30, 2016 at 7:03 AM Alexandre DERUMIER <aderumier at odiso.com> 
> wrote: 
> 
> 
> "Running a fio test also only shows marginal performance difference 
> between scsi-block and scsi-generic" 
> 
> I think that 11% difference is not so marginal. 

Where do you see that 11% difference? 

-device scsi-block 

READ: io=2454.9MB, aggrb=87501KB/s, minb=87501KB/s, maxb=87501KB/s, 
mint=28728msec, maxt=28728msec 
WRITE: io=631997KB, aggrb=21999KB/s, minb=21999KB/s, maxb=21999KB/s, 
mint=28728msec, maxt=28728msec 

-device scsi-generic 
READ: io=2454.9MB, aggrb=88384KB/s, minb=88384KB/s, maxb=88384KB/s, 
mint=28441msec, maxt=28441msec 
WRITE: io=631997KB, aggrb=22221KB/s, minb=22221KB/s, maxb=22221KB/s, 
mint=28441msec, maxt=28441msec