From fe4a330885aee20f233de36085fb15c38094e635 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sun, 20 Nov 2011 20:44:06 +0100 Subject: perf, x86: Implement user-space RDPMC support, to allow fast, user-space access to self-monitoring counters Implement a correct pmu::event_idx for the x86 counter index rules and set CR4.PCE on CPU_STARTING. Signed-off-by: Peter Zijlstra Cc: Stephane Eranian Cc: Arun Sharma Cc: Thomas Gleixner Cc: "H. Peter Anvin" Link: http://lkml.kernel.org/n/tip-mwxab34dibqgzk5zywutfnha@git.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/x86/kernel/cpu') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 5adce1040b11..53b569910175 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1210,6 +1210,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) break; case CPU_STARTING: + set_in_cr4(X86_CR4_PCE); if (x86_pmu.cpu_starting) x86_pmu.cpu_starting(cpu); break; @@ -1542,6 +1543,18 @@ static int x86_pmu_event_init(struct perf_event *event) return err; } +static int x86_pmu_event_idx(struct perf_event *event) +{ + int idx = event->hw.idx; + + if (x86_pmu.num_counters_fixed && idx >= X86_PMC_IDX_FIXED) { + idx -= X86_PMC_IDX_FIXED; + idx |= 1 << 30; + } + + return idx + 1; +} + static struct pmu pmu = { .pmu_enable = x86_pmu_enable, .pmu_disable = x86_pmu_disable, @@ -1557,6 +1570,8 @@ static struct pmu pmu = { .start_txn = x86_pmu_start_txn, .cancel_txn = x86_pmu_cancel_txn, .commit_txn = x86_pmu_commit_txn, + + .event_idx = x86_pmu_event_idx, }; /* -- cgit v1.2.1 From 0c9d42ed4cee2aa1dfc3a260b741baae8615744f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sun, 20 Nov 2011 23:30:47 +0100 Subject: perf, x86: Provide means for disabling userspace RDPMC Allow the disabling of RDPMC via a pmu specific attribute: echo 0 > /sys/bus/event_source/devices/cpu/rdpmc Signed-off-by: Peter Zijlstra Cc: Stephane Eranian Cc: Arun Sharma Link: http://lkml.kernel.org/n/tip-pqeog465zo5hsimtkfz73f27@git.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 55 +++++++++++++++++++++++++++++++++++++++- arch/x86/kernel/cpu/perf_event.h | 8 ++++++ 2 files changed, 62 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/cpu') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 53b569910175..116b040a73a8 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -1210,7 +1211,8 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) break; case CPU_STARTING: - set_in_cr4(X86_CR4_PCE); + if (x86_pmu.attr_rdpmc) + set_in_cr4(X86_CR4_PCE); if (x86_pmu.cpu_starting) x86_pmu.cpu_starting(cpu); break; @@ -1320,6 +1322,8 @@ static int __init init_hw_perf_events(void) } } + x86_pmu.attr_rdpmc = 1; /* enable userspace RDPMC usage by default */ + pr_info("... version: %d\n", x86_pmu.version); pr_info("... bit width: %d\n", x86_pmu.cntval_bits); pr_info("... generic registers: %d\n", x86_pmu.num_counters); @@ -1555,10 +1559,59 @@ static int x86_pmu_event_idx(struct perf_event *event) return idx + 1; } +static ssize_t get_attr_rdpmc(struct device *cdev, + struct device_attribute *attr, + char *buf) +{ + return snprintf(buf, 40, "%d\n", x86_pmu.attr_rdpmc); +} + +static void change_rdpmc(void *info) +{ + bool enable = !!(unsigned long)info; + + if (enable) + set_in_cr4(X86_CR4_PCE); + else + clear_in_cr4(X86_CR4_PCE); +} + +static ssize_t set_attr_rdpmc(struct device *cdev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + unsigned long val = simple_strtoul(buf, NULL, 0); + + if (!!val != !!x86_pmu.attr_rdpmc) { + x86_pmu.attr_rdpmc = !!val; + smp_call_function(change_rdpmc, (void *)val, 1); + } + + return count; +} + +static DEVICE_ATTR(rdpmc, S_IRUSR | S_IWUSR, get_attr_rdpmc, set_attr_rdpmc); + +static struct attribute *x86_pmu_attrs[] = { + &dev_attr_rdpmc.attr, + NULL, +}; + +static struct attribute_group x86_pmu_attr_group = { + .attrs = x86_pmu_attrs, +}; + +static const struct attribute_group *x86_pmu_attr_groups[] = { + &x86_pmu_attr_group, + NULL, +}; + static struct pmu pmu = { .pmu_enable = x86_pmu_enable, .pmu_disable = x86_pmu_disable, + .attr_groups = x86_pmu_attr_groups, + .event_init = x86_pmu_event_init, .add = x86_pmu_add, diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h index 8944062f46e2..513d617b93c4 100644 --- a/arch/x86/kernel/cpu/perf_event.h +++ b/arch/x86/kernel/cpu/perf_event.h @@ -307,6 +307,14 @@ struct x86_pmu { struct x86_pmu_quirk *quirks; int perfctr_second_write; + /* + * sysfs attrs + */ + int attr_rdpmc; + + /* + * CPU Hotplug hooks + */ int (*cpu_prepare)(int cpu); void (*cpu_starting)(int cpu); void (*cpu_dying)(int cpu); -- cgit v1.2.1 From e3f3541c19c89a4daae39300defba68943301949 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 21 Nov 2011 11:43:53 +0100 Subject: perf: Extend the mmap control page with time (TSC) fields Extend the mmap control page with fields so that userspace can compute time deltas relative to the provided time fields. Currently only implemented for x86 with constant and nonstop TSC. Signed-off-by: Peter Zijlstra Cc: Stephane Eranian Cc: Arun Sharma Link: http://lkml.kernel.org/n/tip-3u1jucza77j3wuvs0x2bic0f@git.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'arch/x86/kernel/cpu') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 116b040a73a8..f8bddb5b0600 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -32,6 +32,7 @@ #include #include #include +#include #include "perf_event.h" @@ -1627,6 +1628,19 @@ static struct pmu pmu = { .event_idx = x86_pmu_event_idx, }; +void perf_update_user_clock(struct perf_event_mmap_page *userpg, u64 now) +{ + if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) + return; + + if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC)) + return; + + userpg->time_mult = this_cpu_read(cyc2ns); + userpg->time_shift = CYC2NS_SCALE_FACTOR; + userpg->time_offset = this_cpu_read(cyc2ns_offset) - now; +} + /* * callchain support */ -- cgit v1.2.1