Code: Mainline QEMU (git://git.qemu.org/qemu.git)
Machine: LS21 blade.
Disk: Local disk through VirtIO.
Did not select any cache option. Defaulting to writethrough.
Command tested:
3 parallel instances of : dd if=/dev/zero of=/pmnt/my_pw bs=4k count=100000
QEMU with smp=1
19.3 MB/s + 19.2 MB/s + 18.6 MB/s = 57.1 MB/s
QEMU with smp=4
15.3 MB/s + 14.1 MB/s + 13.6 MB/s = 43.0 MB/s
Is this expected?
Thanks,
JV
=== Details ===
smp = 1
time dd if=/dev/zero of=/pmnt/my_pw bs=4k count=100000 & time dd if=/dev/zero
of=/pmnt/my_pw1 bs=4k count=100000 & time dd if=/dev/zero of=/pmnt/my_pw2 bs=4k
count=100000 &
[r...@localhost ~]# 100000+0 records in
100000+0 records out
409600000 bytes (410 MB) copied, 21.2747 s, 19.3 MB/s
real 0m21.377s
user 0m0.040s
sys 0m1.655s
100000+0 records in
100000+0 records out
409600000 bytes (410 MB) copied, 21.2799 s, 19.2 MB/s
real 0m21.374s
user 0m0.046s
sys 0m1.660s
100000+0 records in
100000+0 records out
409600000 bytes (410 MB) copied, 22.0735 s, 18.6 MB/s
real 0m22.153s
user 0m0.043s
sys 0m1.642s
smp = 4
[r...@localhost ~]# time dd if=/dev/zero of=/pmnt/my_pw bs=4k count=100000 &
time dd if=/dev/zero of=/pmnt/my_pw1 bs=4k count=100000 & time dd if=/dev/zero
of=/pmnt/my_pw2 bs=4k count=100000 &
[r...@localhost ~]# 100000+0 records in
100000+0 records out
409600000 bytes (410 MB) copied, 26.8055 s, 15.3 MB/s
real 0m26.869s
user 0m0.079s
sys 0m3.333s
100000+0 records in
100000+0 records out
409600000 bytes (410 MB) copied, 28.9583 s, 14.1 MB/s
real 0m29.018s
user 0m0.053s
sys 0m4.313s
100000+0 records in
100000+0 records out
409600000 bytes (410 MB) copied, 30.1739 s, 13.6 MB/s
real 0m30.238s
user 0m0.065s
sys 0m4.124s
