From: James Bottomley <James.Bottomley@steeleye.com>
To: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@osdl.org>,
torvalds@osdl.org, davem@davemloft.com, wli@holomorphy.com,
matthew@wil.cx, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: Re: [PATCH 3/3] WorkStruct: Use direct assignment rather than cmpxchg()
Date: Thu, 07 Dec 2006 15:06:37 -0600 [thread overview]
Message-ID: <1165525597.4698.46.camel@mulgrave.il.steeleye.com> (raw)
In-Reply-To: <639.1165521999@redhat.com>
On Thu, 2006-12-07 at 20:06 +0000, David Howells wrote:
> Remember: if you have to put a conditional jump in there, it's going to fail
> one way or the other a certain percentage of the time, and that's going to
> cause a pipeline stall, and these ops are used quite a lot.
That we'd have to put a conditional jump in there is an incorrect
assumption on risc machines. At least on parisc we can do conditional
nullifies in the executing instruction pipeline, so we'd read, nullify
the following write if the bit were set. We do this a lot in our page
interruption handlers.
James
next prev parent reply other threads:[~2006-12-07 21:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-07 15:31 [PATCH 1/3] WorkStruct: Fix up some PA-RISC work items David Howells
2006-12-07 15:31 ` [PATCH 2/3] WorkStruct: Add assign_bits() to give an atomic-bitops safe assignment David Howells
2006-12-07 15:31 ` [PATCH 3/3] WorkStruct: Use direct assignment rather than cmpxchg() David Howells
2006-12-07 16:54 ` Andrew Morton
2006-12-07 20:06 ` David Howells
2006-12-07 21:06 ` Andrew Morton
2006-12-07 21:06 ` James Bottomley [this message]
2006-12-07 21:16 ` David Howells
2006-12-07 22:11 ` David Miller
2006-12-07 23:42 ` Russell King
2006-12-07 23:58 ` David Howells
2006-12-08 11:14 ` Russell King
2006-12-08 13:57 ` David Howells
2006-12-08 3:42 ` [PATCH 1/3] WorkStruct: Fix up some PA-RISC work items Kyle McMartin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1165525597.4698.46.camel@mulgrave.il.steeleye.com \
--to=james.bottomley@steeleye.com \
--cc=akpm@osdl.org \
--cc=davem@davemloft.com \
--cc=dhowells@redhat.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=matthew@wil.cx \
--cc=torvalds@osdl.org \
--cc=wli@holomorphy.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox