FreeBSD 8.0 Performance (at Phoronix)

Alexander Motin mav at
Tue Dec 1 15:22:05 UTC 2009

Alexander Motin wrote:
> Threaded I/O activity could get much benefit from NCQ-aware disk driver.
> It is not included in default FreeBSD kernel, but it would be nice to
> compare.

To check possible NCQ effect, I've built test setup with new 320GB
7200RPM Seagate drive connected to Intel ICH10R controller. I've run
IMHO more reasonable benchmark/raidtest tool from ports on whole device,
to execute pregenerated random mix of 10000 random-sized (512B - 128KB)
read/write requests using default ata(4) driver and new ahci(4):
Number of READ requests: 5029.
Number of WRITE requests: 4971.
Number of bytes to transmit: 655986688.
Number of processes: 32.

The results:
ata(4) - no NCQ:
Bytes per second: 12455402
Requests per second: 189
ahci(4) - with NCQ:
Bytes per second: 19889778
Requests per second: 303

Results are repeatable up to the 4-th digit. Average time per request is
5.29ms and 3.3ms respectively, that seems realistic for this drive.

Alexander Motin

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