Hi,
I plan to use blkcg(proportional BW) in my system. But I encounter
great performance drop after enabling blkcg.
The testing tool is fio(version 2.0.7) and both the BW and IOPS fields
are recorded. Two instances of fio program are carried out simultaneously,
each opearting on a separate disk file (say /data/testfile1,
/data/testfile2).
System environment:
kernel: 3.7.0-rc5
CFQ's slice_idle is disabled(slice_idle=0) while group_idle is
enabled(group_idle=8).
FIO configuration(e.g. "read") for the first fio program(say FIO1):
[global]
description=Emulation of Intel IOmeter File Server Access Pattern
[iometer]
bssplit=4k/30:8k/40:16k/30
rw=read
direct=1
time_based
runtime=180s
ioengine=sync
filename=/data/testfile1
numjobs=32
group_reporting
result before using blkcg: (the value of BW is KB/s)
FIO1 BW/IOPS FIO2 BW/IOPS
---------------------------------------
read 26799/2911 25861/2810
write 138618/15071 138578/15069
rw 72159/7838(r) 71851/7811(r)
72171/7840(w) 71799/7805(w)
randread 4982/543 5370/585
randwrite 5192/566 6010/654
randrw 2369/258(r) 3027/330(r)
2369/258(w) 3016/328(w)
result after using blkcg(create two blkio cgroups with
default blkio.weight(500) and put FIO1 and FIO2 into these
cgroups respectively)
FIO1 BW/IOPS FIO2 BW/IOPS
---------------------------------------
read 36651/3985 36470/3943
write 75738/8229 75641/8221
rw 49169/5342(r) 49168/5346(r)
49200/5348(w) 49140/5341(w)
randread 4876/532 4905/534
randwrite 5535/603 5497/599
randrw 2521/274(r) 2527/275(r)
2510/273(w) 2532/274(w)
Comparing with those results, we found greate performance drop
(30%-40%) in some test cases(especially for the "write", "rw" case).
Is it normal to see write/rw bandwidth decrease by 40% after using
blkio-cgroup? If not, any way to improve or tune the performace?
Thanks.
--
Regards,
Zhao Shuai
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/containers
