Messages in this thread Patch in this message | | | From | Alex Shi <> | Subject | [PATCH v4 7/7] x86/tlb: add tlb_flushall_factor into sysfs for user testing/tuning | Date | Thu, 10 May 2012 13:00:13 +0800 |
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kernel will replace cr3 rewrite with invlpg when tlb_flush_entries <= active_tlb_entries / 2^tlb_flushall_factor if tlb_flushall_factor is -1, kernel won't do this replacement.
User can modify its value according to specific applications.
Signed-off-by: Alex Shi <alex.shi@intel.com> --- Documentation/ABI/testing/sysfs-devices-system-cpu | 12 ++++++ arch/x86/Kconfig.debug | 11 ++++++ arch/x86/kernel/cpu/common.c | 37 ++++++++++++++++++++ drivers/base/cpu.c | 4 ++ include/linux/cpu.h | 4 ++ 5 files changed, 68 insertions(+), 0 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index e7be75b..05f8eb7 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -78,6 +78,18 @@ Description: Dynamic addition and removal of CPU's. This is not hotplug the system. Information writtento the file to remove CPU's is architecture specific. +What: /sys/devices/system/cpu/tlb_flushall_factor +Date: May 2012 +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> +Description: tlb_flushall_factor show and setting interface + tlb_flushall_factor shows the balance point in replacing cr3 + writting with multiple 'invlpg'. It will do this replacement + when flush_tlb_lines <= active_lines/2^tlb_flushall_factor + If tlb_flushall_factor is -1, means the replacement will be + disabled. + + User can set this for the specific CPU or application. + What: /sys/devices/system/cpu/cpu#/node Date: October 2009 Contact: Linux memory management mailing list <linux-mm@kvack.org> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index e46c214..5b87493 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -129,6 +129,17 @@ config DOUBLEFAULT option saves about 4k and might cause you much additional grey hair. +config DEBUG_TLBFLUSH + bool "Enable user level tlb flush all setting" + depends on DEBUG_KERNEL && (X86_64 || X86_INVLPG) + ---help--- + This option allows user tune tlb_flushall_factor knob that under + /sys/devices/system/cpu, set to -1 means do tlb flush all for any + multiple tlb lines evacuation demand. Otherwise kernel will use + multiple 'invlpg' for the demand when + flush_lines <= active_tlb_lines / 2^tlb_flushall_factor + If in doubt, say "N" + config IOMMU_DEBUG bool "Enable IOMMU debugging" depends on GART_IOMMU && DEBUG_KERNEL diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 8879d20..d1986c6 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -481,6 +481,43 @@ void __cpuinit cpu_detect_tlb(struct cpuinfo_x86 *c) tlb_flushall_factor); } +#ifdef CONFIG_DEBUG_TLBFLUSH +static ssize_t __tlb_flushall_factor_store(const char *buf, + size_t count, int smt) +{ + short factor = 0; + + if (sscanf(buf, "%hd", &factor) != 1) + return -EINVAL; + + tlb_flushall_factor = factor; + + return count; +} + +static ssize_t tlb_flushall_factor_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "%hd\n", tlb_flushall_factor); +} +static ssize_t tlb_flushall_factor_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return __tlb_flushall_factor_store(buf, count, 0); +} + +static DEVICE_ATTR(tlb_flushall_factor, 0644, + tlb_flushall_factor_show, + tlb_flushall_factor_store); + +int __init create_sysfs_tlb_flushall_factor(struct device *dev) +{ + return device_create_file(dev, &dev_attr_tlb_flushall_factor); +} +#endif + void __cpuinit detect_ht(struct cpuinfo_x86 *c) { #ifdef CONFIG_X86_HT diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index adf937b..dc0f77b 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -331,6 +331,10 @@ void __init cpu_dev_init(void) cpu_dev_register_generic(); +#ifdef CONFIG_DEBUG_TLBFLUSH + create_sysfs_tlb_flushall_factor(cpu_subsys.dev_root); +#endif + #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) sched_create_sysfs_power_savings_entries(cpu_subsys.dev_root); #endif diff --git a/include/linux/cpu.h b/include/linux/cpu.h index ee28844..3eb85a5 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -36,6 +36,10 @@ extern void cpu_remove_dev_attr(struct device_attribute *attr); extern int cpu_add_dev_attr_group(struct attribute_group *attrs); extern void cpu_remove_dev_attr_group(struct attribute_group *attrs); +#ifdef CONFIG_DEBUG_TLBFLUSH +extern int create_sysfs_tlb_flushall_factor(struct device *dev); +#endif + extern int sched_create_sysfs_power_savings_entries(struct device *dev); #ifdef CONFIG_HOTPLUG_CPU -- 1.7.5.4
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