cfq performance gap
From: Avantika Mathur
Date: Thu Dec 07 2006 - 19:05:19 EST
Hi Jens,
I've noticed a performance gap between the cfq scheduler and other io
schedulers when running the rawio benchmark.
Results from rawio on 2.6.19, cfq and noop schedulers:
CFQ:
procs device num read KB/sec I/O Ops/sec
----- --------------- ---------- ------- --------------
16 /dev/sda 16412 8338 2084
----- --------------- ---------- ------- --------------
16 16412 8338 2084
Total run time 0.492072 seconds
NOOP:
procs device num read KB/sec I/O Ops/sec
----- --------------- ---------- ------- --------------
16 /dev/sda 16399 29224 7306
----- --------------- ---------- ------- --------------
16 16399 29224 7306
Total run time 0.140284 seconds
The benchmark workload is 16 processes running 4k random reads.
Is this performance gap a known issue?
Thanks,
Avantika Mathur
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