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Re: HEADS-UP: SATA NCQ support merged (from jdolecek-ncq branch)

I've fixed the compilation for ALL kernels.

2017-10-10 17:34 GMT+02:00 Michael <>:
> I tried sequential reads ( dd if=/dev/rwd0c ... ) and throughput took a
> significant hit. I used to get about 120MB/s with the siisata, now it
> fluctuates between 80 and 90MB/s, ahcisata dropped from about 80MB/s to
> 70MB/s. Both spinning rust of varying vintage.
> I should probably do a bonnie run on either one before & after to see
> if there's any change in random access.

I've seen this on one of my disks, too. It seems it's much slower in NCQ mode. I think the firmware might not utilise the disk cache properly when in NCQ mode.

You can try switching it off via sysctl, hw.wdX.use_ncq. You can also try to turn off use_ncq_prio if that makes any difference.

We might need to introduce some heuristics for this.


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