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



Hello,

On Tue, 10 Oct 2017 23:11:54 +0200
Jaromír Doleček <jaromir.dolecek%gmail.com@localhost> wrote:

> 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.

/home/ml# sysctl -w hw.wd1.use_ncq=0
hw.wd1.use_ncq: 1 -> 0
/home/ml# dd if=/dev/rwd1c of=/dev/null bs=1m count=2048
2048+0 records in
2048+0 records out
2147483648 bytes transferred in 21.747 secs (98748500 bytes/sec)

/home/ml# sysctl -w hw.wd1.use_ncq=1
hw.wd1.use_ncq: 0 -> 1
/home/ml# dd if=/dev/rwd1c of=/dev/null bs=1m count=2048
2048+0 records in
2048+0 records out
2147483648 bytes transferred in 26.125 secs (82200331 bytes/sec)

/home/ml# sysctl -w hw.wd1.use_ncq_prio=0
hw.wd1.use_ncq_prio: 1 -> 0
/home/ml# dd if=/dev/rwd1c of=/dev/null bs=1m count=2048
2048+0 records in
2048+0 records out
2147483648 bytes transferred in 24.187 secs (88786689 bytes/sec)

... that's the siisata:
siisata0 at pci0 dev 2 function 0: vendor 1095 product 3124 (rev. 0x02)
siisata0: interrupting at ivec 700
siisata0: SiI3124, 3.0Gb/s
siisata0: 64-bit 66MHz PCI

... with one of these:

siisata0 port 0: device present, speed: 3.0Gb/s
wd1(siisata0:0:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100) (using DMA), NCQ (30 tags) w/PRIO

Model: WDC WD5000AAKX-083CA1, Rev: 17.01H17, Serial #:      WD-WCAYUCL72135
World Wide Name: 50014EE104595309
Device type: ATA, fixed
Capacity 500 Gbytes, 976773168 sectors, 512 bytes/sector
Cylinders: 16383, heads: 16, sec/track: 63
...
Serial ATA capabilities:
        1.5Gb/s signaling
        3.0Gb/s signaling
        6.0Gb/s signaling
        Native Command Queuing
        PHY Event Counters

have fun
Michael


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