Re: howto boost write(2) performance?

From: Michael Tokarev
Date: Tue Oct 09 2007 - 12:26:33 EST


Boaz Harrosh wrote:
[]
> If your target is a SCSI target you can gain up to 15% by using
> sg. Search on the net for the "sg utils" package. The source code
> of sg_dd and others are a grate example of how to do it.
>
> Other wise O_DIRECT is your friend. Also look for asynchronous
> I/O so you have a few pending IO buffers to keep the pipes full.

What's the advantage of sg_io over O_DIRECT to the block device?
I think sg devices are being (slowly?) obsoleted since most stuff
which has been in sg now works over normal block device, no?
At least, I haven't seen any significant difference between
sg_dd and dd with oflag=direct.

Thanks.

/mjt
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