From: Mark Lord <liml@rtr.ca>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Richard Scobie <r.scobie@clear.net.nz>, linux-ide@vger.kernel.org
Subject: Re: SAS v SATA interface performance
Date: Fri, 30 Nov 2007 22:06:31 -0500 [thread overview]
Message-ID: <4750CFB7.7040400@rtr.ca> (raw)
In-Reply-To: <20071201001740.7ffce6f6@the-village.bc.nu>
Alan Cox wrote:
>> The comment I saw, which I'm trying to verify, mentioned the SATA drives
>> "held the bus" or similar longer than SAS ones.
>
> SATA normally uses one link per device so the device side isn't contended
> unless you descend into the murky world of port multipliers.
..
And that's where NCQ comes into it's own, allowing full bus release
so that other drives on the same port multiplier can burst as needed.
I've only had a port multiplier here for a few days, and used only a pair
of *notebook* SATA drives on it thus far. Both drives can stream at full
rate without any slowdown -- that's 55MByte/sec from each drive, at the
same time, for sequential reading, 100MByte/sec total. Notebook drives.
Cheers
next prev parent reply other threads:[~2007-12-01 3:06 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-01 0:04 SAS v SATA interface performance Richard Scobie
2007-12-01 0:17 ` Alan Cox
2007-12-01 3:06 ` Mark Lord [this message]
2007-12-10 7:15 ` Tejun Heo
2007-12-10 16:23 ` Mark Lord
-- strict thread matches above, loose matches on Subject: below --
2007-11-30 19:19 Richard Scobie
2007-11-30 21:24 ` Michael Tokarev
2007-11-30 23:17 ` Alan Cox
2007-12-01 7:43 ` Richard Scobie
2007-12-01 14:37 ` Greg Freemyer
2007-12-01 19:19 ` Richard Scobie
2007-12-01 20:01 ` Mark Lord
2007-12-01 20:40 ` Jeff Garzik
2007-12-01 23:55 ` Richard Scobie
2007-12-02 3:45 ` Mark Lord
2007-12-02 3:49 ` Mark Lord
2007-12-10 7:33 ` Tejun Heo
2007-12-10 14:36 ` Jens Axboe
2007-12-10 16:28 ` Mark Lord
2007-12-10 14:50 ` James Bottomley
2007-12-10 16:32 ` Mark Lord
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