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authorEric Lammerts <eric@lammerts.org>2005-07-31 22:34:42 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-08-01 19:13:59 -0700
commitcdf32eaa4e601b15146e21b6470de00f149ce37f (patch)
treeb57d079ef6cd4318aaae485d2abe03d6b38a51d3
parent3fef3fa24d8d1bb6d82cad195f73917fa6534dac (diff)
downloadconfigs-cdf32eaa4e601b15146e21b6470de00f149ce37f.tar.gz
[PATCH] disable addres space randomization default on transmeta CPUs
We know that the randomisation slows down some workloads on Transmeta CPUs by quite large amounts. We think it's because the CPU needs to recode the same x86 instructions when they pop up at a different virtual address after a fork+exec. So disable randomization by default on those CPUs. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/cpu/transmeta.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpu/transmeta.c b/arch/i386/kernel/cpu/transmeta.c
index f57e5ee9494..d8e59e19867 100644
--- a/arch/i386/kernel/cpu/transmeta.c
+++ b/arch/i386/kernel/cpu/transmeta.c
@@ -76,6 +76,10 @@ static void __init init_transmeta(struct cpuinfo_x86 *c)
#define USER686 (X86_FEATURE_TSC|X86_FEATURE_CX8|X86_FEATURE_CMOV)
if ( c->x86 == 5 && (c->x86_capability[0] & USER686) == USER686 )
c->x86 = 6;
+
+ /* randomize_va_space slows us down enormously;
+ it probably triggers retranslation of x86->native bytecode */
+ randomize_va_space = 0;
}
static void transmeta_identify(struct cpuinfo_x86 * c)