From: Ingo Molnar <mingo@elte.hu>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>,
Keith Owens <kaos@ocs.com.au>,
David.Mosberger@acm.org, Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org
Subject: Re: Add prefetch switch stack hook in scheduler function
Date: Fri, 29 Jul 2005 10:44:44 +0200 [thread overview]
Message-ID: <20050729084444.GC7302@elte.hu> (raw)
In-Reply-To: <42E9E91B.9050403@cosmosbay.com>
* Eric Dumazet <dada1@cosmosbay.com> wrote:
> Please test that len is a constant, or else the inlining is too large
> for the non constant case.
yeah. fix below.
Ingo
-----
noticed by Eric Dumazet: unrolling should be dependent on a constant
length, otherwise inlining gets too large.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
include/linux/prefetch.h | 128 ++++++++++++++++++++++++-----------------------
1 files changed, 66 insertions(+), 62 deletions(-)
Index: linux-prefetch-task/include/linux/prefetch.h
===================================================================
--- linux-prefetch-task.orig/include/linux/prefetch.h
+++ linux-prefetch-task/include/linux/prefetch.h
@@ -64,37 +64,39 @@ static inline void prefetch_range(void *
/*
* Unroll agressively:
*/
- if (len <= PREFETCH_STRIDE)
- prefetch(cp);
- else if (len <= 2*PREFETCH_STRIDE) {
- prefetch(cp);
- prefetch(cp + PREFETCH_STRIDE);
- }
- else if (len <= 3*PREFETCH_STRIDE) {
- prefetch(cp);
- prefetch(cp + PREFETCH_STRIDE);
- prefetch(cp + 2*PREFETCH_STRIDE);
- }
- else if (len <= 4*PREFETCH_STRIDE) {
- prefetch(cp);
- prefetch(cp + PREFETCH_STRIDE);
- prefetch(cp + 2*PREFETCH_STRIDE);
- prefetch(cp + 3*PREFETCH_STRIDE);
- }
- else if (len <= 5*PREFETCH_STRIDE) {
- prefetch(cp);
- prefetch(cp + PREFETCH_STRIDE);
- prefetch(cp + 2*PREFETCH_STRIDE);
- prefetch(cp + 3*PREFETCH_STRIDE);
- prefetch(cp + 4*PREFETCH_STRIDE);
- }
- else if (len <= 6*PREFETCH_STRIDE) {
- prefetch(cp);
- prefetch(cp + PREFETCH_STRIDE);
- prefetch(cp + 2*PREFETCH_STRIDE);
- prefetch(cp + 3*PREFETCH_STRIDE);
- prefetch(cp + 4*PREFETCH_STRIDE);
- prefetch(cp + 5*PREFETCH_STRIDE);
+ if (__builtin_constant_p(len) && (len <= 6*PREFETCH_STRIDE)) {
+ if (len <= PREFETCH_STRIDE)
+ prefetch(cp);
+ else if (len <= 2*PREFETCH_STRIDE) {
+ prefetch(cp);
+ prefetch(cp + PREFETCH_STRIDE);
+ }
+ else if (len <= 3*PREFETCH_STRIDE) {
+ prefetch(cp);
+ prefetch(cp + PREFETCH_STRIDE);
+ prefetch(cp + 2*PREFETCH_STRIDE);
+ }
+ else if (len <= 4*PREFETCH_STRIDE) {
+ prefetch(cp);
+ prefetch(cp + PREFETCH_STRIDE);
+ prefetch(cp + 2*PREFETCH_STRIDE);
+ prefetch(cp + 3*PREFETCH_STRIDE);
+ }
+ else if (len <= 5*PREFETCH_STRIDE) {
+ prefetch(cp);
+ prefetch(cp + PREFETCH_STRIDE);
+ prefetch(cp + 2*PREFETCH_STRIDE);
+ prefetch(cp + 3*PREFETCH_STRIDE);
+ prefetch(cp + 4*PREFETCH_STRIDE);
+ }
+ else if (len <= 6*PREFETCH_STRIDE) {
+ prefetch(cp);
+ prefetch(cp + PREFETCH_STRIDE);
+ prefetch(cp + 2*PREFETCH_STRIDE);
+ prefetch(cp + 3*PREFETCH_STRIDE);
+ prefetch(cp + 4*PREFETCH_STRIDE);
+ prefetch(cp + 5*PREFETCH_STRIDE);
+ }
} else
for (; cp < end; cp += PREFETCH_STRIDE)
prefetch(cp);
@@ -110,37 +112,39 @@ static inline void prefetchw_range(void
/*
* Unroll agressively:
*/
- if (len <= PREFETCH_STRIDE)
- prefetchw(cp);
- else if (len <= 2*PREFETCH_STRIDE) {
- prefetchw(cp);
- prefetchw(cp + PREFETCH_STRIDE);
- }
- else if (len <= 3*PREFETCH_STRIDE) {
- prefetchw(cp);
- prefetchw(cp + PREFETCH_STRIDE);
- prefetchw(cp + 2*PREFETCH_STRIDE);
- }
- else if (len <= 4*PREFETCH_STRIDE) {
- prefetchw(cp);
- prefetchw(cp + PREFETCH_STRIDE);
- prefetchw(cp + 2*PREFETCH_STRIDE);
- prefetchw(cp + 3*PREFETCH_STRIDE);
- }
- else if (len <= 5*PREFETCH_STRIDE) {
- prefetchw(cp);
- prefetchw(cp + PREFETCH_STRIDE);
- prefetchw(cp + 2*PREFETCH_STRIDE);
- prefetchw(cp + 3*PREFETCH_STRIDE);
- prefetchw(cp + 4*PREFETCH_STRIDE);
- }
- else if (len <= 6*PREFETCH_STRIDE) {
- prefetchw(cp);
- prefetchw(cp + PREFETCH_STRIDE);
- prefetchw(cp + 2*PREFETCH_STRIDE);
- prefetchw(cp + 3*PREFETCH_STRIDE);
- prefetchw(cp + 4*PREFETCH_STRIDE);
- prefetchw(cp + 5*PREFETCH_STRIDE);
+ if (__builtin_constant_p(len) && (len <= 6*PREFETCH_STRIDE)) {
+ if (len <= PREFETCH_STRIDE)
+ prefetchw(cp);
+ else if (len <= 2*PREFETCH_STRIDE) {
+ prefetchw(cp);
+ prefetchw(cp + PREFETCH_STRIDE);
+ }
+ else if (len <= 3*PREFETCH_STRIDE) {
+ prefetchw(cp);
+ prefetchw(cp + PREFETCH_STRIDE);
+ prefetchw(cp + 2*PREFETCH_STRIDE);
+ }
+ else if (len <= 4*PREFETCH_STRIDE) {
+ prefetchw(cp);
+ prefetchw(cp + PREFETCH_STRIDE);
+ prefetchw(cp + 2*PREFETCH_STRIDE);
+ prefetchw(cp + 3*PREFETCH_STRIDE);
+ }
+ else if (len <= 5*PREFETCH_STRIDE) {
+ prefetchw(cp);
+ prefetchw(cp + PREFETCH_STRIDE);
+ prefetchw(cp + 2*PREFETCH_STRIDE);
+ prefetchw(cp + 3*PREFETCH_STRIDE);
+ prefetchw(cp + 4*PREFETCH_STRIDE);
+ }
+ else if (len <= 6*PREFETCH_STRIDE) {
+ prefetchw(cp);
+ prefetchw(cp + PREFETCH_STRIDE);
+ prefetchw(cp + 2*PREFETCH_STRIDE);
+ prefetchw(cp + 3*PREFETCH_STRIDE);
+ prefetchw(cp + 4*PREFETCH_STRIDE);
+ prefetchw(cp + 5*PREFETCH_STRIDE);
+ }
} else
for (; cp < end; cp += PREFETCH_STRIDE)
prefetchw(cp);
next prev parent reply other threads:[~2005-07-29 8:45 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-27 22:07 Add prefetch switch stack hook in scheduler function Chen, Kenneth W
2005-07-27 23:13 ` Andrew Morton
2005-07-27 23:23 ` david mosberger
2005-07-28 7:41 ` Ingo Molnar
2005-07-28 8:09 ` Keith Owens
2005-07-28 8:16 ` Ingo Molnar
2005-07-28 9:09 ` Ingo Molnar
2005-07-28 19:14 ` Chen, Kenneth W
2005-07-29 7:04 ` Ingo Molnar
2005-07-29 7:07 ` Ingo Molnar
2005-07-29 8:30 ` Eric Dumazet
2005-07-29 8:44 ` Ingo Molnar [this message]
2005-07-31 16:27 ` hashed spinlocks Daniel Walker
2005-07-31 18:46 ` David S. Miller
2005-07-31 19:06 ` Daniel Walker
2005-07-31 19:11 ` David S. Miller
2005-07-31 19:16 ` Daniel Walker
2005-07-29 8:30 ` Add prefetch switch stack hook in scheduler function Chen, Kenneth W
2005-07-29 8:35 ` Ingo Molnar
2005-07-29 8:39 ` Chen, Kenneth W
2005-07-29 9:17 ` Peter Zijlstra
2005-07-29 10:52 ` Ingo Molnar
2005-07-29 7:22 ` Chen, Kenneth W
2005-07-29 7:45 ` Keith Owens
2005-07-29 8:02 ` Chen, Kenneth W
2005-07-29 8:28 ` Ingo Molnar
2005-07-29 9:02 ` Russell King
2005-07-29 9:45 ` Ingo Molnar
2005-07-29 7:38 ` Keith Owens
2005-07-29 8:08 ` Chen, Kenneth W
2005-07-28 8:31 ` Nick Piggin
2005-07-28 8:35 ` Ingo Molnar
2005-07-28 8:48 ` Nick Piggin
2005-07-28 9:16 ` Ingo Molnar
2005-07-28 9:19 ` Ingo Molnar
2005-07-28 9:34 ` Nick Piggin
2005-07-28 10:04 ` Ingo Molnar
2005-07-28 10:29 ` Nick Piggin
-- strict thread matches above, loose matches on Subject: below --
2005-07-29 15:18 linux
2005-07-29 15:49 ` Ingo Molnar
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