From: Eric Lammerts Date: Mon, 1 Aug 2005 05:34:42 +0000 (-0700) Subject: [PATCH] disable addres space randomization default on transmeta CPUs X-Git-Tag: v2.6.13-rc5~28 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cdf32eaa4e601b15146e21b6470de00f149ce37f;p=linux-2.6 [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 Signed-off-by: Linus Torvalds --- diff --git a/arch/i386/kernel/cpu/transmeta.c b/arch/i386/kernel/cpu/transmeta.c index f57e5ee949..d8e59e1986 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)