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powernow-k8: Add core performance boost support
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, make the CPB code hotplug-aware so that taking cores offline wouldn't interfere with boosting the remaining online cores. Furthermore, add cpu_online_mask hotplug protection as suggested by Andrew. Finally, cleanup the driver init codepath and update copyrights. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> LKML-Reference: <1270065406-1814-3-git-send-email-bp@amd64.org> Reviewed-by: Thomas Renninger <trenn@suse.de> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Borislav Petkov
H. Peter Anvin
parent
5958f1d5d7
commit
73860c6b2f
@ -1,6 +1,5 @@
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/*
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* (c) 2003-2006 Advanced Micro Devices, Inc.
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* (c) 2003-2010 Advanced Micro Devices, Inc.
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* Your use of this code is subject to the terms and conditions of the
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* GNU general public license version 2. See "COPYING" or
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* http://www.gnu.org/licenses/gpl.html
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@ -54,6 +53,10 @@ static DEFINE_PER_CPU(struct powernow_k8_data *, powernow_data);
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static int cpu_family = CPU_OPTERON;
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/* core performance boost */
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static bool cpb_capable, cpb_enabled;
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static struct msr __percpu *msrs;
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#ifndef CONFIG_SMP
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static inline const struct cpumask *cpu_core_mask(int cpu)
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{
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@ -1393,8 +1396,77 @@ out:
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return khz;
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}
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static void _cpb_toggle_msrs(bool t)
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{
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int cpu;
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get_online_cpus();
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rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
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for_each_cpu(cpu, cpu_online_mask) {
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struct msr *reg = per_cpu_ptr(msrs, cpu);
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if (t)
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reg->l &= ~BIT(25);
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else
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reg->l |= BIT(25);
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}
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wrmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
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put_online_cpus();
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}
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/*
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* Switch on/off core performance boosting.
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*
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* 0=disable
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* 1=enable.
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*/
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static void cpb_toggle(bool t)
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{
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if (!cpb_capable)
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return;
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if (t && !cpb_enabled) {
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cpb_enabled = true;
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_cpb_toggle_msrs(t);
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printk(KERN_INFO PFX "Core Boosting enabled.\n");
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} else if (!t && cpb_enabled) {
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cpb_enabled = false;
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_cpb_toggle_msrs(t);
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printk(KERN_INFO PFX "Core Boosting disabled.\n");
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}
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}
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static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
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size_t count)
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{
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int ret = -EINVAL;
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unsigned long val = 0;
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ret = strict_strtoul(buf, 10, &val);
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if (!ret && (val == 0 || val == 1) && cpb_capable)
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cpb_toggle(val);
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else
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return -EINVAL;
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return count;
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}
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static ssize_t show_cpb(struct cpufreq_policy *policy, char *buf)
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{
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return sprintf(buf, "%u\n", cpb_enabled);
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}
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#define define_one_rw(_name) \
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static struct freq_attr _name = \
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__ATTR(_name, 0644, show_##_name, store_##_name)
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define_one_rw(cpb);
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static struct freq_attr *powernow_k8_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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&cpb,
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NULL,
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};
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@ -1410,10 +1482,51 @@ static struct cpufreq_driver cpufreq_amd64_driver = {
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.attr = powernow_k8_attr,
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};
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/*
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* Clear the boost-disable flag on the CPU_DOWN path so that this cpu
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* cannot block the remaining ones from boosting. On the CPU_UP path we
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* simply keep the boost-disable flag in sync with the current global
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* state.
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*/
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static int __cpuinit cpb_notify(struct notifier_block *nb, unsigned long action,
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void *hcpu)
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{
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unsigned cpu = (long)hcpu;
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u32 lo, hi;
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switch (action) {
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case CPU_UP_PREPARE:
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case CPU_UP_PREPARE_FROZEN:
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if (!cpb_enabled) {
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rdmsr_on_cpu(cpu, MSR_K7_HWCR, &lo, &hi);
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lo |= BIT(25);
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wrmsr_on_cpu(cpu, MSR_K7_HWCR, lo, hi);
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}
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break;
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case CPU_DOWN_PREPARE:
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case CPU_DOWN_PREPARE_FROZEN:
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rdmsr_on_cpu(cpu, MSR_K7_HWCR, &lo, &hi);
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lo &= ~BIT(25);
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wrmsr_on_cpu(cpu, MSR_K7_HWCR, lo, hi);
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break;
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default:
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block __cpuinitdata cpb_nb = {
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.notifier_call = cpb_notify,
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};
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/* driver entry point for init */
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static int __cpuinit powernowk8_init(void)
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{
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unsigned int i, supported_cpus = 0;
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unsigned int i, supported_cpus = 0, cpu;
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for_each_online_cpu(i) {
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int rc;
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@ -1422,15 +1535,36 @@ static int __cpuinit powernowk8_init(void)
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supported_cpus++;
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}
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if (supported_cpus == num_online_cpus()) {
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printk(KERN_INFO PFX "Found %d %s "
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"processors (%d cpu cores) (" VERSION ")\n",
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num_online_nodes(),
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boot_cpu_data.x86_model_id, supported_cpus);
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return cpufreq_register_driver(&cpufreq_amd64_driver);
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if (supported_cpus != num_online_cpus())
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return -ENODEV;
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printk(KERN_INFO PFX "Found %d %s (%d cpu cores) (" VERSION ")\n",
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num_online_nodes(), boot_cpu_data.x86_model_id, supported_cpus);
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if (boot_cpu_has(X86_FEATURE_CPB)) {
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cpb_capable = true;
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register_cpu_notifier(&cpb_nb);
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msrs = msrs_alloc();
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if (!msrs) {
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printk(KERN_ERR "%s: Error allocating msrs!\n", __func__);
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return -ENOMEM;
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}
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rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
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for_each_cpu(cpu, cpu_online_mask) {
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struct msr *reg = per_cpu_ptr(msrs, cpu);
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cpb_enabled |= !(!!(reg->l & BIT(25)));
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}
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printk(KERN_INFO PFX "Core Performance Boosting: %s.\n",
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(cpb_enabled ? "on" : "off"));
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}
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return -ENODEV;
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return cpufreq_register_driver(&cpufreq_amd64_driver);
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}
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/* driver entry point for term */
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@ -1438,6 +1572,13 @@ static void __exit powernowk8_exit(void)
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{
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dprintk("exit\n");
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if (boot_cpu_has(X86_FEATURE_CPB)) {
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msrs_free(msrs);
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msrs = NULL;
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unregister_cpu_notifier(&cpb_nb);
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}
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cpufreq_unregister_driver(&cpufreq_amd64_driver);
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}
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@ -5,7 +5,6 @@
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* http://www.gnu.org/licenses/gpl.html
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*/
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enum pstate {
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HW_PSTATE_INVALID = 0xff,
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HW_PSTATE_0 = 0,
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@ -55,7 +54,6 @@ struct powernow_k8_data {
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struct cpumask *available_cores;
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};
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/* processor's cpuid instruction support */
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#define CPUID_PROCESSOR_SIGNATURE 1 /* function 1 */
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#define CPUID_XFAM 0x0ff00000 /* extended family */
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