Re: I/O read, write implementation questions

From: Brent Casavant <bcasavan_at_sgi.com>
Date: 2006-04-27 01:53:53
On Wed, 26 Apr 2006, Brent Casavant wrote:

> Note that wmb() is not sufficient for writes, at least on SGI Altix.
> wmb() ensures that the write has issued from the processor, however
> it does not ensure that the I/O device itself has seen the write.
> The mmiowb() is the appropriate call to ensure that the write has
> been seen.

Oh, and lest I confuse anyone, wmb() is sufficient for writes to RAM.
It's only I/O writes for which it is insufficient.

Brent

-- 
Brent Casavant                          All music is folk music.  I ain't
bcasavan@sgi.com                        never heard a horse sing a song.
Silicon Graphics, Inc.                    -- Louis Armstrong
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Received on Thu Apr 27 01:54:32 2006

This archive was generated by hypermail 2.1.8 : 2006-04-27 01:54:43 EST