diff options
| author | Andi Kleen <ak@suse.de> | 2007-05-02 19:27:12 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:12 +0200 |
| commit | f039b754714a422959027cb18bb33760eb8153f0 (patch) | |
| tree | c5f28502adf35f5ea7738a974cd7c4fc81e1dd21 /arch/x86_64/kernel | |
| parent | c169859d6dfc7471ef9f2dbd720936e17906a084 (diff) | |
[PATCH] x86: Don't use MWAIT on AMD Family 10
It doesn't put the CPU into deeper sleep states, so it's better to use the standard
idle loop to save power. But allow to reenable it anyways for benchmarking.
I also removed the obsolete idle=halt on i386
Cc: andreas.herrmann@amd.com
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/kernel')
| -rw-r--r-- | arch/x86_64/kernel/process.c | 12 | ||||
| -rw-r--r-- | arch/x86_64/kernel/setup.c | 6 |
2 files changed, 13 insertions, 5 deletions
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index d8d5ccc245c..4f21765078b 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -288,16 +288,18 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) static int __init idle_setup (char *str) { - if (!strncmp(str, "poll", 4)) { + if (!strcmp(str, "poll")) { printk("using polling idle threads.\n"); pm_idle = poll_idle; - } + } else if (!strcmp(str, "mwait")) + force_mwait = 1; + else + return -1; boot_option_idle_override = 1; - return 1; + return 0; } - -__setup("idle=", idle_setup); +early_param("idle", idle_setup); /* Prints also some state that isn't saved in the pt_regs */ void __show_regs(struct pt_regs * regs) diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c index 0a1d539149d..db30b5bcef6 100644 --- a/arch/x86_64/kernel/setup.c +++ b/arch/x86_64/kernel/setup.c @@ -79,6 +79,8 @@ int bootloader_type; unsigned long saved_video_mode; +int force_mwait __cpuinitdata; + /* * Early DMI memory */ @@ -604,6 +606,10 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) /* RDTSC can be speculated around */ clear_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability); + + /* Family 10 doesn't support C states in MWAIT so don't use it */ + if (c->x86 == 0x10 && !force_mwait) + clear_bit(X86_FEATURE_MWAIT, &c->x86_capability); } static void __cpuinit detect_ht(struct cpuinfo_x86 *c) |