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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-06-02 16:46:57 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-06-02 21:45:32 +0200 |
commit | 08247e31ca79b8f02cce47b7e8120797a8726606 (patch) | |
tree | 1094dc286ba5033904d07d256f7d739abb4d421d | |
parent | 8e3747c13c39246c7e46def7cf495d9d21d4c5f9 (diff) | |
download | op-kernel-dev-08247e31ca79b8f02cce47b7e8120797a8726606.zip op-kernel-dev-08247e31ca79b8f02cce47b7e8120797a8726606.tar.gz |
perf_counter: Add ioctl for changing the sample period/frequency
Reported-by: Stephane Eranian <eranian@googlemail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r-- | include/linux/perf_counter.h | 9 | ||||
-rw-r--r-- | kernel/perf_counter.c | 41 |
2 files changed, 46 insertions, 4 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index c046f7d..45bdd3b 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -164,10 +164,11 @@ struct perf_counter_hw_event { /* * Ioctls that can be done on a perf counter fd: */ -#define PERF_COUNTER_IOC_ENABLE _IOW('$', 0, u32) -#define PERF_COUNTER_IOC_DISABLE _IOW('$', 1, u32) -#define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32) -#define PERF_COUNTER_IOC_RESET _IOW('$', 3, u32) +#define PERF_COUNTER_IOC_ENABLE _IO ('$', 0) +#define PERF_COUNTER_IOC_DISABLE _IO ('$', 1) +#define PERF_COUNTER_IOC_REFRESH _IO ('$', 2) +#define PERF_COUNTER_IOC_RESET _IO ('$', 3) +#define PERF_COUNTER_IOC_PERIOD _IOW('$', 4, u64) enum perf_counter_ioc_flags { PERF_IOC_FLAG_GROUP = 1U << 0, diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 3f11a2b..abe2f3b 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1604,6 +1604,43 @@ static void perf_counter_for_each(struct perf_counter *counter, mutex_unlock(&counter->child_mutex); } +static int perf_counter_period(struct perf_counter *counter, u64 __user *arg) +{ + struct perf_counter_context *ctx = counter->ctx; + unsigned long size; + int ret = 0; + u64 value; + + if (!counter->hw_event.sample_period) + return -EINVAL; + + size = copy_from_user(&value, arg, sizeof(value)); + if (size != sizeof(value)) + return -EFAULT; + + if (!value) + return -EINVAL; + + spin_lock_irq(&ctx->lock); + if (counter->hw_event.freq) { + if (value > sysctl_perf_counter_limit) { + ret = -EINVAL; + goto unlock; + } + + counter->hw_event.sample_freq = value; + } else { + counter->hw_event.sample_period = value; + counter->hw.sample_period = value; + + perf_log_period(counter, value); + } +unlock: + spin_unlock_irq(&ctx->lock); + + return ret; +} + static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct perf_counter *counter = file->private_data; @@ -1623,6 +1660,10 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case PERF_COUNTER_IOC_REFRESH: return perf_counter_refresh(counter, arg); + + case PERF_COUNTER_IOC_PERIOD: + return perf_counter_period(counter, (u64 __user *)arg); + default: return -ENOTTY; } |