From: Andreas Krebbel <krebbel@linux.vnet.ibm.com>
To: "Fang, Changpeng" <Changpeng.Fang@amd.com>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
borntraeger@de.ibm.com
Subject: Re: [PATCH] Enabling Software Prefetching by Default at -O3
Date: Fri, 18 Jun 2010 09:13:00 -0000 [thread overview]
Message-ID: <4C1B3087.9060001@linux.vnet.ibm.com> (raw)
In-Reply-To: <D4C76825A6780047854A11E93CDE84D02F7743@SAUSEXMBP01.amd.com>
Hi,
> This patch serves as a proposal to turn on software prefetching by default at -O3.
On S/390 I ran into a problem with the runtime of the prefetching pass when using
aggressive loop unrolling. There is an algorithm with quadratic runtime regarding the
memory references which causes a very long compile time. Christian already opened a
bugzilla for that (PR 44576). It probably would make sense to have a closer look at this
before enabling the pass by default. Perhaps we could simply limit the miss rate
computation to a certain amount of memory references?
Besides of that enabling the prefetching pass by default is ok with me. I think it would
help getting more people into improving it.
Bye,
-Andreas-
next prev parent reply other threads:[~2010-06-18 8:38 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-15 22:21 Fang, Changpeng
2010-06-15 22:24 ` H.J. Lu
2010-06-15 22:28 ` Fang, Changpeng
2010-06-15 22:44 ` H.J. Lu
2010-06-15 22:47 ` Fang, Changpeng
2010-06-15 23:42 ` Mark Mitchell
2010-06-16 0:30 ` H.J. Lu
2010-06-16 3:43 ` Mark Mitchell
2010-06-18 8:51 ` Christian Borntraeger
2010-06-18 18:00 ` Fang, Changpeng
2010-06-19 0:30 ` H.J. Lu
2010-06-20 0:11 ` Christian Borntraeger
2010-06-20 2:34 ` Mark Mitchell
2010-06-20 4:29 ` Andi Kleen
2010-06-22 23:40 ` Fang, Changpeng
2010-06-23 6:21 ` Christian Borntraeger
2010-06-23 9:26 ` Richard Guenther
2010-06-23 12:02 ` Joseph S. Myers
2010-06-23 12:30 ` Christian Borntraeger
2010-06-23 13:13 ` Manuel López-Ibáñez
2010-06-24 23:37 ` Fang, Changpeng
2010-06-25 11:48 ` Richard Guenther
2010-06-25 20:16 ` Sebastian Pop
2010-06-26 17:01 ` Richard Guenther
2010-06-26 17:30 ` Richard Guenther
2010-06-26 17:38 ` Jan Hubicka
2010-06-26 18:23 ` Jan Hubicka
2010-06-25 12:29 ` Christian Borntraeger
2010-07-02 12:46 ` [PATCH] Enabling Software Prefetching by Default@-O3 Ulrich Weigand
2010-06-18 9:13 ` Andreas Krebbel [this message]
2010-06-18 9:26 ` [PATCH] Enabling Software Prefetching by Default at -O3 Andreas Krebbel
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