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From: David Woodhouse <dwmw2@infradead.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: ppc-dev <linuxppc-dev@ozlabs.org>, paulus@samba.org
Subject: Re: [POWERPC] merge iSeries i/o operations with the rest
Date: Mon, 04 Sep 2006 22:07:50 -0700	[thread overview]
Message-ID: <1157432871.2413.9.camel@shinybook.infradead.org> (raw)
In-Reply-To: <20060905120817.e52857ee.sfr@canb.auug.org.au>

On Tue, 2006-09-05 at 12:08 +1000, Stephen Rothwell wrote:
> The low level i/o operations are now handled in iSeires by taking a
> trap when we access the (inaccessible) io memory region and calling
> the Hypervisor from the trap code.  

There was some discussion of the possibility of using the 'alternatives'
mechanism to patch the I/O instructions at run-time when we find we've
booted on iSeries -- just turning each one into a jump to a trampoline
which does the appropriate hypervisor calls, thus avoiding the overhead
of the trap each time.

Was that approach not viable, or not noticeably less of a performance
hit on iSeries?

-- 
dwmw2

  reply	other threads:[~2006-09-05  5:07 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-05  2:08 [POWERPC] merge iSeries i/o operations with the rest Stephen Rothwell
2006-09-05  5:07 ` David Woodhouse [this message]
2006-09-05  5:39   ` Stephen Rothwell
2006-09-05 16:41 ` Linas Vepstas
2006-09-05 23:19   ` Stephen Rothwell
2006-09-06  8:24 ` Stephen Rothwell
2006-09-18  5:38 ` Stephen Rothwell
2006-09-20 12:15   ` Stephen Rothwell
2006-09-20 16:01     ` Hollis Blanchard
2006-09-21  0:03       ` Stephen Rothwell
2006-09-21  0:20         ` Michael Ellerman
2006-09-21  4:55           ` [POWERPC] mark BUG() as noreturn Stephen Rothwell
2006-09-21 12:18             ` Jimi Xenidis
2006-09-22  0:54               ` Michael Ellerman
2006-09-22  1:34                 ` Amos Waterland
2006-09-22 10:58                 ` Jimi Xenidis
2006-09-21 13:23             ` David Howells
2006-09-21 15:15               ` Segher Boessenkool
2006-09-21  8:00         ` [POWERPC] merge iSeries i/o operations with the rest Stephen Rothwell

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