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/* -*- linux-c -*-
* Perf Functions
* Copyright (C) 2006 Red Hat Inc.
* Copyright (C) 2010 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _PERF_C_
#define _PERF_C_
#include <linux/perf_event.h>
#include "perf.h"
/** @file perf.c
* @brief Implements performance monitoring hardware support
*/
/** Initialize performance sampling
* Call this during probe initialization to set up performance event sampling
* for all online cpus. Returns ERR_PTR on error.
*
* @param attr description of event to sample
* @param callback function to call when perf event overflows
* @param pp associated probe point
* @param ph probe handler
*/
static Perf *_stp_perf_init (struct perf_event_attr *attr,
perf_overflow_handler_t callback,
const char *pp, void (*ph) (struct context *) )
{
long rc = -EINVAL;
int cpu;
Perf *pe;
pe = (Perf *) _stp_kmalloc (sizeof(Perf));
if (pe == NULL)
return ERR_PTR(-ENOMEM);
/* allocate space for the event descriptor for each cpu */
pe->pd = (perfcpu *) _stp_alloc_percpu (sizeof(perfcpu));
if (pe->pd == NULL) {
rc = -ENOMEM;
goto exit1;
}
/* initialize event on each processor */
stp_for_each_cpu(cpu) {
perfcpu *pd = per_cpu_ptr (pe->pd, cpu);
struct perf_event **event = &(pd->event);
if (cpu_is_offline(cpu)) {
*event = NULL;
continue;
}
*event = perf_event_create_kernel_counter(attr, cpu, -1,
callback);
if (IS_ERR(*event)) {
rc = PTR_ERR(*event);
*event = NULL;
goto exit2;
}
pd->pp = pp;
pd->ph = ph;
}
return pe;
exit2:
stp_for_each_cpu(cpu) {
perfcpu *pd = per_cpu_ptr (pe->pd, cpu);
struct perf_event **event = &(pd->event);
if (*event) perf_event_release_kernel(*event);
}
_stp_free_percpu(pe->pd);
exit1:
_stp_kfree(pe);
return ERR_PTR(rc);
}
/** Delete performance event.
* Call this to shutdown performance event sampling
*
* @param pe
*/
static void _stp_perf_del (Perf *pe)
{
if (pe) {
int cpu;
/* shut down performance event sampling */
stp_for_each_cpu(cpu) {
perfcpu *pd = per_cpu_ptr (pe->pd, cpu);
struct perf_event **event = &(pd->event);
if (*event) {
perf_event_release_kernel(*event);
}
}
_stp_free_percpu (pe->pd);
_stp_kfree (pe);
}
}
#endif /* _PERF_C_ */
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