From: jbarnes@sgi.com (Jesse Barnes)
To: linux-ia64@vger.kernel.org
Subject: [PATCH] don't use ld.bias
Date: Mon, 21 Jul 2003 23:55:59 +0000 [thread overview]
Message-ID: <marc-linux-ia64-105883179830025@msgid-missing> (raw)
Patch to fix spin_lock to not use ld.bias since it causes a bunch of bus
activity that hurts scalability when a lock is contended.
Thanks,
Jesse
=== include/asm-ia64/spinlock.h 1.13 vs edited ==--- 1.13/include/asm-ia64/spinlock.h Fri May 30 19:59:40 2003
+++ edited/include/asm-ia64/spinlock.h Mon Jul 21 16:54:15 2003
@@ -93,13 +93,16 @@
* Streamlined test_and_set_bit(0, (x)). We use test-and-test-and-set
* rather than a simple xchg to avoid writing the cache-line when
* there is contention.
+ *
+ * Don't use ld.bias since it generates unnecessary bus activity on
+ * multiprocessor systems when the lock is contended.
*/
#define _raw_spin_lock(x) __asm__ __volatile__ ( \
"mov ar.ccv = r0\n" \
"mov r29 = 1\n" \
";;\n" \
"1:\n" \
- "ld4.bias r2 = [%0]\n" \
+ "ld4 r2 = [%0]\n" \
";;\n" \
"cmp4.eq p0,p7 = r0,r2\n" \
"(p7) br.cond.spnt.few 1b \n" \
next reply other threads:[~2003-07-21 23:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-21 23:55 Jesse Barnes [this message]
2003-07-22 0:15 ` [PATCH] don't use ld.bias Chen, Kenneth W
2003-07-22 13:11 ` Jesse Barnes
2003-07-23 4:40 ` Mallick, Asit K
2003-07-23 12:00 ` Matthew Wilcox
2003-07-25 1:10 ` David Mosberger
2003-07-25 13:40 ` Jesse Barnes
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