From: Borislav Petkov <borislav.petkov@xxxxxxx> Starting with F10h, revE, AMD processors add support for a dynamic core boosting feature called Core Performance Boost. When a specific condition is present, a subset of the cores on a system are boosted beyond their P0 operating frequency to speed up the performance of single-threaded applications. In the normal case, the system comes out of reset with core boosting enabled. This patch adds a sysfs knob with which core boosting can be switched on or off for benchmarking purposes. While at it, cleanup the driver init codepath and update copyrights. Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx> Reviewed-by: Thomas Renninger <trenn@xxxxxxx> --- arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 110 ++++++++++++++++++++++++++--- arch/x86/kernel/cpu/cpufreq/powernow-k8.h | 2 - 2 files changed, 100 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c index d360b56..b86daa6 100644 --- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c +++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c @@ -1,6 +1,5 @@ - /* - * (c) 2003-2006 Advanced Micro Devices, Inc. + * (c) 2003-2010 Advanced Micro Devices, Inc. * Your use of this code is subject to the terms and conditions of the * GNU general public license version 2. See "COPYING" or * http://www.gnu.org/licenses/gpl.html @@ -54,6 +53,10 @@ static DEFINE_PER_CPU(struct powernow_k8_data *, powernow_data); static int cpu_family = CPU_OPTERON; +/* core performance boost */ +static bool cpb_capable, cpb_enabled; +static struct msr __percpu *msrs; + #ifndef CONFIG_SMP static inline const struct cpumask *cpu_core_mask(int cpu) { @@ -1393,8 +1396,73 @@ out: return khz; } +static void _cpb_toggle_msrs(bool t) +{ + int cpu; + + rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs); + + for_each_cpu(cpu, cpu_online_mask) { + struct msr *reg = per_cpu_ptr(msrs, cpu); + if (t) + reg->l &= ~BIT(25); + else + reg->l |= BIT(25); + } + wrmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs); +} + +/* + * Switch on/off core performance boosting. + * + * 0=disable + * 1=enable. + */ +static void cpb_toggle(bool t) +{ + if (!cpb_capable) + return; + + if (t && !cpb_enabled) { + cpb_enabled = true; + _cpb_toggle_msrs(t); + printk(KERN_INFO PFX "Core Boosting enabled.\n"); + } else if (!t && cpb_enabled) { + cpb_enabled = false; + _cpb_toggle_msrs(t); + printk(KERN_INFO PFX "Core Boosting disabled.\n"); + } +} + +static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf, + size_t count) +{ + int ret = -EINVAL; + unsigned long val = 0; + + ret = strict_strtoul(buf, 10, &val); + if (!ret && (val == 0 || val == 1) && cpb_capable) + cpb_toggle(val); + else + return -EINVAL; + + return count; +} + +static ssize_t show_cpb(struct cpufreq_policy *policy, char *buf) +{ + return sprintf(buf, "%u\n", cpb_enabled); +} + +#define define_one_rw(_name) \ +static struct freq_attr _name = \ +__ATTR(_name, 0644, show_##_name, store_##_name) + +define_one_rw(cpb); + static struct freq_attr *powernow_k8_attr[] = { &cpufreq_freq_attr_scaling_available_freqs, + &cpb, NULL, }; @@ -1413,7 +1481,7 @@ static struct cpufreq_driver cpufreq_amd64_driver = { /* driver entry point for init */ static int __cpuinit powernowk8_init(void) { - unsigned int i, supported_cpus = 0; + unsigned int i, supported_cpus = 0, cpu; for_each_online_cpu(i) { int rc; @@ -1422,15 +1490,34 @@ static int __cpuinit powernowk8_init(void) supported_cpus++; } - if (supported_cpus == num_online_cpus()) { - printk(KERN_INFO PFX "Found %d %s " - "processors (%d cpu cores) (" VERSION ")\n", - num_online_nodes(), - boot_cpu_data.x86_model_id, supported_cpus); - return cpufreq_register_driver(&cpufreq_amd64_driver); + if (supported_cpus != num_online_cpus()) + return -ENODEV; + + printk(KERN_INFO PFX "Found %d %s (%d cpu cores) (" VERSION ")\n", + num_online_nodes(), boot_cpu_data.x86_model_id, supported_cpus); + + if (boot_cpu_has(X86_FEATURE_CPB)) { + + cpb_capable = true; + + msrs = msrs_alloc(); + if (!msrs) { + printk(KERN_ERR "%s: Error allocating msrs!\n", __func__); + return -ENOMEM; + } + + rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs); + + for_each_cpu(cpu, cpu_online_mask) { + struct msr *reg = per_cpu_ptr(msrs, cpu); + cpb_enabled |= !(!!(reg->l & BIT(25))); + } + + printk(KERN_INFO PFX "Core Performance Boosting: %s.\n", + (cpb_enabled ? "on" : "off")); } - return -ENODEV; + return cpufreq_register_driver(&cpufreq_amd64_driver); } /* driver entry point for term */ @@ -1438,6 +1525,9 @@ static void __exit powernowk8_exit(void) { dprintk("exit\n"); + msrs_free(msrs); + msrs = NULL; + cpufreq_unregister_driver(&cpufreq_amd64_driver); } diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.h b/arch/x86/kernel/cpu/cpufreq/powernow-k8.h index 02ce824..df3529b 100644 --- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.h +++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.h @@ -5,7 +5,6 @@ * http://www.gnu.org/licenses/gpl.html */ - enum pstate { HW_PSTATE_INVALID = 0xff, HW_PSTATE_0 = 0, @@ -55,7 +54,6 @@ struct powernow_k8_data { struct cpumask *available_cores; }; - /* processor's cpuid instruction support */ #define CPUID_PROCESSOR_SIGNATURE 1 /* function 1 */ #define CPUID_XFAM 0x0ff00000 /* extended family */ -- 1.7.0 -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
