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 MotinReceived on Tue Dec 01 2009 - 14:22:05 UTC
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