diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 11 | ||||
| -rw-r--r-- | arch/i386/kernel/cpu/amd.c | 5 | ||||
| -rw-r--r-- | arch/i386/kernel/process.c | 17 | ||||
| -rw-r--r-- | arch/x86_64/kernel/process.c | 12 | ||||
| -rw-r--r-- | arch/x86_64/kernel/setup.c | 6 | ||||
| -rw-r--r-- | include/asm-i386/processor.h | 2 | ||||
| -rw-r--r-- | include/asm-x86_64/proto.h | 2 |
7 files changed, 39 insertions, 16 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4287696f18d..94ce0d20253 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -695,8 +695,15 @@ and is between 256 and 4096 characters. It is defined in the file idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed See Documentation/ide.txt. - idle= [HW] - Format: idle=poll or idle=halt + idle= [X86] + Format: idle=poll or idle=mwait + Poll forces a polling idle loop that can slightly improves the performance + of waking up a idle CPU, but will use a lot of power and make the system + run hot. Not recommended. + idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose + to not use it because it doesn't save as much power as a normal idle + loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same + as idle=poll. ignore_loglevel [KNL] Ignore loglevel setting - this will print /all/ diff --git a/arch/i386/kernel/cpu/amd.c b/arch/i386/kernel/cpu/amd.c index 2d47db48297..197cda62caa 100644 --- a/arch/i386/kernel/cpu/amd.c +++ b/arch/i386/kernel/cpu/amd.c @@ -53,6 +53,8 @@ static __cpuinit int amd_apic_timer_broken(void) return 0; } +int force_mwait __cpuinitdata; + static void __cpuinit init_amd(struct cpuinfo_x86 *c) { u32 l, h; @@ -275,6 +277,9 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) if (amd_apic_timer_broken()) set_bit(X86_FEATURE_LAPIC_TIMER_BROKEN, c->x86_capability); + + if (c->x86 == 0x10 && !force_mwait) + clear_bit(X86_FEATURE_MWAIT, c->x86_capability); } static unsigned int __cpuinit amd_size_cache(struct cpuinfo_x86 * c, unsigned int size) diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index 393a67d5d94..7e8e129b3d7 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -272,25 +272,24 @@ void __devinit select_idle_routine(const struct cpuinfo_x86 *c) } } -static int __init idle_setup (char *str) +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; #ifdef CONFIG_X86_SMP if (smp_num_siblings > 1) printk("WARNING: polling idle and HT enabled, performance may degrade.\n"); #endif - } else if (!strncmp(str, "halt", 4)) { - printk("using halt in idle threads.\n"); - pm_idle = default_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); void show_regs(struct pt_regs * regs) { 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) diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h index 9d895cc2f31..882d3f8fbba 100644 --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -779,4 +779,6 @@ extern int sysenter_setup(void); extern void cpu_set_gdt(int); extern void cpu_init(void); +extern int force_mwait; + #endif /* __ASM_I386_PROCESSOR_H */ diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h index 3f8f285138d..98063bcb3b3 100644 --- a/include/asm-x86_64/proto.h +++ b/include/asm-x86_64/proto.h @@ -119,6 +119,8 @@ extern int gsi_irq_sharing(int gsi); extern void smp_local_timer_interrupt(void); +extern int force_mwait; + long do_arch_prctl(struct task_struct *task, int code, unsigned long addr); void i8254_timer_resume(void); |