perf tools: Unify perf.data mapping and events handling

This librarizes the perf.data file mapping and handling in various
perf tools, roughly reducing the amount of code and fixing the
places that mmap from beginning of the file whereas we want to mmap
from the beginning of the data, leading to page fault because the
mmap window is too small since the trace info are written in the
file too.

TODO:

 - convert perf timechart too

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <20091007104729.GD5043@nowhere>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 253 insertions, 0 deletions

diff --git a/tools/perf/util/data_map.c b/tools/perf/util/data_map.c
new file mode 100644
index 00000000000..242b0555ab9
--- /dev/null
+++ b/tools/perf/util/data_map.c
@@ -0,0 +1,222 @@
+#include "data_map.h"
+#include "symbol.h"
+#include "util.h"
+#include "debug.h"
+
+
+static struct perf_file_handler *curr_handler;
+static unsigned long	mmap_window = 32;
+static char		__cwd[PATH_MAX];
+
+static int
+process_event_stub(event_t *event __used,
+		   unsigned long offset __used,
+		   unsigned long head __used)
+{
+	return 0;
+}
+
+void register_perf_file_handler(struct perf_file_handler *handler)
+{
+	if (!handler->process_sample_event)
+		handler->process_sample_event = process_event_stub;
+	if (!handler->process_mmap_event)
+		handler->process_mmap_event = process_event_stub;
+	if (!handler->process_comm_event)
+		handler->process_comm_event = process_event_stub;
+	if (!handler->process_fork_event)
+		handler->process_fork_event = process_event_stub;
+	if (!handler->process_exit_event)
+		handler->process_exit_event = process_event_stub;
+	if (!handler->process_lost_event)
+		handler->process_lost_event = process_event_stub;
+	if (!handler->process_read_event)
+		handler->process_read_event = process_event_stub;
+	if (!handler->process_throttle_event)
+		handler->process_throttle_event = process_event_stub;
+	if (!handler->process_unthrottle_event)
+		handler->process_unthrottle_event = process_event_stub;
+
+	curr_handler = handler;
+}
+
+static int
+process_event(event_t *event, unsigned long offset, unsigned long head)
+{
+	trace_event(event);
+
+	switch (event->header.type) {
+	case PERF_RECORD_SAMPLE:
+		return curr_handler->process_sample_event(event, offset, head);
+	case PERF_RECORD_MMAP:
+		return curr_handler->process_mmap_event(event, offset, head);
+	case PERF_RECORD_COMM:
+		return curr_handler->process_comm_event(event, offset, head);
+	case PERF_RECORD_FORK:
+		return curr_handler->process_fork_event(event, offset, head);
+	case PERF_RECORD_EXIT:
+		return curr_handler->process_exit_event(event, offset, head);
+	case PERF_RECORD_LOST:
+		return curr_handler->process_lost_event(event, offset, head);
+	case PERF_RECORD_READ:
+		return curr_handler->process_read_event(event, offset, head);
+	case PERF_RECORD_THROTTLE:
+		return curr_handler->process_throttle_event(event, offset, head);
+	case PERF_RECORD_UNTHROTTLE:
+		return curr_handler->process_unthrottle_event(event, offset, head);
+	default:
+		curr_handler->total_unknown++;
+		return -1;
+	}
+}
+
+int mmap_dispatch_perf_file(struct perf_header **pheader,
+			    const char *input_name,
+			    int force,
+			    int full_paths,
+			    int *cwdlen,
+			    char **cwd)
+{
+	int ret, rc = EXIT_FAILURE;
+	struct perf_header *header;
+	unsigned long head, shift;
+	unsigned long offset = 0;
+	struct stat input_stat;
+	size_t	page_size;
+	u64 sample_type;
+	event_t *event;
+	uint32_t size;
+	int input;
+	char *buf;
+
+	if (!curr_handler)
+		die("Forgot to register perf file handler");
+
+	page_size = getpagesize();
+
+	input = open(input_name, O_RDONLY);
+	if (input < 0) {
+		fprintf(stderr, " failed to open file: %s", input_name);
+		if (!strcmp(input_name, "perf.data"))
+			fprintf(stderr, "  (try 'perf record' first)");
+		fprintf(stderr, "\n");
+		exit(-1);
+	}
+
+	ret = fstat(input, &input_stat);
+	if (ret < 0) {
+		perror("failed to stat file");
+		exit(-1);
+	}
+
+	if (!force && input_stat.st_uid && (input_stat.st_uid != geteuid())) {
+		fprintf(stderr, "file: %s not owned by current user or root\n",
+			input_name);
+		exit(-1);
+	}
+
+	if (!input_stat.st_size) {
+		fprintf(stderr, "zero-sized file, nothing to do!\n");
+		exit(0);
+	}
+
+	*pheader = perf_header__read(input);
+	header = *pheader;
+	head = header->data_offset;
+
+	sample_type = perf_header__sample_type(header);
+
+	if (curr_handler->sample_type_check)
+		if (curr_handler->sample_type_check(sample_type) < 0)
+			exit(-1);
+
+	if (load_kernel() < 0) {
+		perror("failed to load kernel symbols");
+		return EXIT_FAILURE;
+	}
+
+	if (!full_paths) {
+		if (getcwd(__cwd, sizeof(__cwd)) == NULL) {
+			perror("failed to get the current directory");
+			return EXIT_FAILURE;
+		}
+		*cwd = __cwd;
+		*cwdlen = strlen(*cwd);
+	} else {
+		*cwd = NULL;
+		*cwdlen = 0;
+	}
+
+	shift = page_size * (head / page_size);
+	offset += shift;
+	head -= shift;
+
+remap:
+	buf = (char *)mmap(NULL, page_size * mmap_window, PROT_READ,
+			   MAP_SHARED, input, offset);
+	if (buf == MAP_FAILED) {
+		perror("failed to mmap file");
+		exit(-1);
+	}
+
+more:
+	event = (event_t *)(buf + head);
+
+	size = event->header.size;
+	if (!size)
+		size = 8;
+
+	if (head + event->header.size >= page_size * mmap_window) {
+		int munmap_ret;
+
+		shift = page_size * (head / page_size);
+
+		munmap_ret = munmap(buf, page_size * mmap_window);
+		assert(munmap_ret == 0);
+
+		offset += shift;
+		head -= shift;
+		goto remap;
+	}
+
+	size = event->header.size;
+
+	dump_printf("\n%p [%p]: event: %d\n",
+			(void *)(offset + head),
+			(void *)(long)event->header.size,
+			event->header.type);
+
+	if (!size || process_event(event, offset, head) < 0) {
+
+		dump_printf("%p [%p]: skipping unknown header type: %d\n",
+			(void *)(offset + head),
+			(void *)(long)(event->header.size),
+			event->header.type);
+
+		/*
+		 * assume we lost track of the stream, check alignment, and
+		 * increment a single u64 in the hope to catch on again 'soon'.
+		 */
+
+		if (unlikely(head & 7))
+			head &= ~7ULL;
+
+		size = 8;
+	}
+
+	head += size;
+
+	if (offset + head >= header->data_offset + header->data_size)
+		goto done;
+
+	if (offset + head < (unsigned long)input_stat.st_size)
+		goto more;
+
+done:
+	rc = EXIT_SUCCESS;
+	close(input);
+
+	return rc;
+}
+
+
diff --git a/tools/perf/util/data_map.h b/tools/perf/util/data_map.h
new file mode 100644
index 00000000000..716d1053b07
--- /dev/null
+++ b/tools/perf/util/data_map.h
@@ -0,0 +1,31 @@
+#ifndef __PERF_DATAMAP_H
+#define __PERF_DATAMAP_H
+
+#include "event.h"
+#include "header.h"
+
+typedef int (*event_type_handler_t)(event_t *, unsigned long, unsigned long);
+
+struct perf_file_handler {
+	event_type_handler_t	process_sample_event;
+	event_type_handler_t	process_mmap_event;
+	event_type_handler_t	process_comm_event;
+	event_type_handler_t	process_fork_event;
+	event_type_handler_t	process_exit_event;
+	event_type_handler_t	process_lost_event;
+	event_type_handler_t	process_read_event;
+	event_type_handler_t	process_throttle_event;
+	event_type_handler_t	process_unthrottle_event;
+	int			(*sample_type_check)(u64 sample_type);
+	unsigned long		total_unknown;
+};
+
+void register_perf_file_handler(struct perf_file_handler *handler);
+int mmap_dispatch_perf_file(struct perf_header **pheader,
+			    const char *input_name,
+			    int force,
+			    int full_paths,
+			    int *cwdlen,
+			    char **cwd);
+
+#endif