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Commit 70082dd9 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf evsel: Introduce mmap support 



Out of the code in 'perf top'. Record is next in line.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent dd7927f4

tools/perf/builtin-top.c

+5 −66
Original line number Diff line number Diff line
@@ -1095,43 +1095,12 @@ static void event__process_sample(const event_t *self, 
	}

}



struct mmap_data {

	void			*base;

	int			mask;

	unsigned int		prev;

};



static int perf_evsel__alloc_mmap_per_thread(struct perf_evsel *evsel,

					     int ncpus, int nthreads)

{

	evsel->priv = xyarray__new(ncpus, nthreads, sizeof(struct mmap_data));

	return evsel->priv != NULL ? 0 : -ENOMEM;

}



static void perf_evsel__free_mmap(struct perf_evsel *evsel)

{

	xyarray__delete(evsel->priv);

	evsel->priv = NULL;

}



static unsigned int mmap_read_head(struct mmap_data *md)

{

	struct perf_event_mmap_page *pc = md->base;

	int head;



	head = pc->data_head;

	rmb();



	return head;

}



static void perf_session__mmap_read_counter(struct perf_session *self,

					    struct perf_evsel *evsel,

					    int cpu, int thread_idx)

{

	struct xyarray *mmap_array = evsel->priv;

	struct mmap_data *md = xyarray__entry(mmap_array, cpu, thread_idx);

	unsigned int head = mmap_read_head(md);

	struct perf_mmap *md = xyarray__entry(evsel->mmap, cpu, thread_idx);

	unsigned int head = perf_mmap__read_head(md);

	unsigned int old = md->prev;

	unsigned char *data = md->base + page_size;

	struct sample_data sample;
@@ -1210,35 +1179,9 @@ static void perf_session__mmap_read(struct perf_session *self) 
	}

}



static void start_counter(int i, struct perf_evlist *evlist,

			  struct perf_evsel *evsel)

{

	struct xyarray *mmap_array = evsel->priv;

	struct mmap_data *mm;

	int thread_index;



	for (thread_index = 0; thread_index < threads->nr; thread_index++) {

		assert(FD(evsel, i, thread_index) >= 0);

		fcntl(FD(evsel, i, thread_index), F_SETFL, O_NONBLOCK);



		evlist->pollfd[evlist->nr_fds].fd = FD(evsel, i, thread_index);

		evlist->pollfd[evlist->nr_fds].events = POLLIN;

		evlist->nr_fds++;



		mm = xyarray__entry(mmap_array, i, thread_index);

		mm->prev = 0;

		mm->mask = mmap_pages*page_size - 1;

		mm->base = mmap(NULL, (mmap_pages+1)*page_size,

				PROT_READ, MAP_SHARED, FD(evsel, i, thread_index), 0);

		if (mm->base == MAP_FAILED)

			die("failed to mmap with %d (%s)\n", errno, strerror(errno));

	}

}



static void start_counters(struct perf_evlist *evlist)

{

	struct perf_evsel *counter;

	int i;



	list_for_each_entry(counter, &evlist->entries, node) {

		struct perf_event_attr *attr = &counter->attr;
@@ -1282,11 +1225,9 @@ static void start_counters(struct perf_evlist *evlist) 
			die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");

			exit(-1);

		}

	}



	for (i = 0; i < cpus->nr; i++) {

		list_for_each_entry(counter, &evlist->entries, node)

			start_counter(i, evsel_list, counter);

		if (perf_evsel__mmap(counter, cpus, threads, mmap_pages, evlist) < 0)

			die("failed to mmap with %d (%s)\n", errno, strerror(errno));

	}

}
@@ -1453,7 +1394,7 @@ int cmd_top(int argc, const char **argv, const char *prefix __used) 
		usage_with_options(top_usage, options);



	list_for_each_entry(pos, &evsel_list->entries, node) {

		if (perf_evsel__alloc_mmap_per_thread(pos, cpus->nr, threads->nr) < 0 ||

		if (perf_evsel__alloc_mmap(pos, cpus->nr, threads->nr) < 0 ||

		    perf_evsel__alloc_fd(pos, cpus->nr, threads->nr) < 0)

			goto out_free_fd;

		/*
@@ -1485,8 +1426,6 @@ int cmd_top(int argc, const char **argv, const char *prefix __used) 


	status = __cmd_top();

out_free_fd:

	list_for_each_entry(pos, &evsel_list->entries, node)

		perf_evsel__free_mmap(pos);

	perf_evlist__delete(evsel_list);



	return status;

tools/perf/perf.h

+14 −0
Original line number Diff line number Diff line
@@ -94,6 +94,20 @@ void get_term_dimensions(struct winsize *ws); 
#include "util/types.h"

#include <stdbool.h>



struct perf_mmap {

	void			*base;

	int			mask;

	unsigned int		prev;

};



static inline unsigned int perf_mmap__read_head(struct perf_mmap *mm)

{

	struct perf_event_mmap_page *pc = mm->base;

	int head = pc->data_head;

	rmb();

	return head;

}



/*

 * prctl(PR_TASK_PERF_EVENTS_DISABLE) will (cheaply) disable all

 * counters in the current task.

tools/perf/util/evlist.c

+8 −0
Original line number Diff line number Diff line
@@ -60,3 +60,11 @@ int perf_evlist__alloc_pollfd(struct perf_evlist *evlist, int ncpus, int nthread 
	evlist->pollfd = malloc(sizeof(struct pollfd) * nfds);

	return evlist->pollfd != NULL ? 0 : -ENOMEM;

}



void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)

{

	fcntl(fd, F_SETFL, O_NONBLOCK);

	evlist->pollfd[evlist->nr_fds].fd = fd;

	evlist->pollfd[evlist->nr_fds].events = POLLIN;

	evlist->nr_fds++;

}

tools/perf/util/evlist.h

+1 −0
Original line number Diff line number Diff line
@@ -21,5 +21,6 @@ void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry); 
int perf_evlist__add_default(struct perf_evlist *evlist);



int perf_evlist__alloc_pollfd(struct perf_evlist *evlist, int ncpus, int nthreads);

void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd);



#endif /* __PERF_EVLIST_H */

tools/perf/util/evsel.c

+71 −0
Original line number Diff line number Diff line 
#include "evsel.h"

#include "evlist.h"

#include "../perf.h"

#include "util.h"

#include "cpumap.h"

#include "thread.h"



#include <unistd.h>

#include <sys/mman.h>



#define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))



struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr, int idx)
@@ -49,10 +53,32 @@ void perf_evsel__close_fd(struct perf_evsel *evsel, int ncpus, int nthreads) 
		}

}



void perf_evsel__munmap(struct perf_evsel *evsel, int ncpus, int nthreads)

{

	struct perf_mmap *mm;

	int cpu, thread;



	for (cpu = 0; cpu < ncpus; cpu++)

		for (thread = 0; thread < nthreads; ++thread) {

			mm = xyarray__entry(evsel->mmap, cpu, thread);

			if (mm->base != NULL) {

				munmap(mm->base, evsel->mmap_len);

				mm->base = NULL;

			}

		}

}



int perf_evsel__alloc_mmap(struct perf_evsel *evsel, int ncpus, int nthreads)

{

	evsel->mmap = xyarray__new(ncpus, nthreads, sizeof(struct perf_mmap));

	return evsel->mmap != NULL ? 0 : -ENOMEM;

}



void perf_evsel__delete(struct perf_evsel *evsel)

{

	assert(list_empty(&evsel->node));

	xyarray__delete(evsel->fd);

	xyarray__delete(evsel->mmap);

	free(evsel);

}
@@ -208,3 +234,48 @@ int perf_evsel__open_per_thread(struct perf_evsel *evsel, 
{

	return __perf_evsel__open(evsel, &empty_cpu_map.map, threads, group, inherit);

}



int perf_evsel__mmap(struct perf_evsel *evsel, struct cpu_map *cpus,

		     struct thread_map *threads, int pages,

		     struct perf_evlist *evlist)

{

	unsigned int page_size = sysconf(_SC_PAGE_SIZE);

	int mask = pages * page_size - 1, cpu;

	struct perf_mmap *mm;

	int thread;



	if (evsel->mmap == NULL &&

	    perf_evsel__alloc_mmap(evsel, cpus->nr, threads->nr) < 0)

		return -ENOMEM;



	evsel->mmap_len = (pages + 1) * page_size;



	for (cpu = 0; cpu < cpus->nr; cpu++) {

		for (thread = 0; thread < threads->nr; thread++) {

			mm = xyarray__entry(evsel->mmap, cpu, thread);

			mm->prev = 0;

			mm->mask = mask;

			mm->base = mmap(NULL, evsel->mmap_len, PROT_READ,

					MAP_SHARED, FD(evsel, cpu, thread), 0);

			if (mm->base == MAP_FAILED)

				goto out_unmap;



			if (evlist != NULL)

				 perf_evlist__add_pollfd(evlist, FD(evsel, cpu, thread));

		}

	}



	return 0;



out_unmap:

	do {

		while (--thread >= 0) {

			mm = xyarray__entry(evsel->mmap, cpu, thread);

			munmap(mm->base, evsel->mmap_len);

			mm->base = NULL;

		}

		thread = threads->nr;

	} while (--cpu >= 0);



	return -1;

}