[PATCH] disable addres space randomization default on transmeta CPUs

cdf32eaa · Eric Lammerts <[email protected]> · 2005-07-31 22:34:42 -07:00

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 <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: cdf32eaa4e601b15146e21b6470de00f149ce37f
Parents: 3fef3fa2

Changes

1 files changed · +4 −0

File	Status	Add	Del	Content
arch/i386/kernel/cpu/transmeta.c	modified	+4	−0	View file

arch/i386/kernel/cpu/transmeta.c

View file

diff --git a/arch/i386/kernel/cpu/transmeta.c b/arch/i386/kernel/cpu/transmeta.c
index f57e5ee..d8e59e1 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)