perf: Add pipe-specific header read/write and event processing code
This patch makes several changes to allow the perf event stream
to be sent and received over a pipe:
- adds pipe-specific versions of the header read/write code
- adds pipe-specific version of the event processing code
- adds a range of event types to be used for header or other
pseudo events, above the range used by the kernel
- checks the return value of event handlers, which they can use
to skip over large events during event processing rather than actually
reading them into event objects.
- unifies the multiple do_read() functions and updates its
users.
Note that none of these changes affect the existing perf data
file format or processing - this code only comes into play if
perf output is sent to stdout (or is read from stdin).
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
Cc: k-keiichi@bx.jp.nec.com
Cc: acme@ghostprotocols.net
LKML-Reference: <1270184365-8281-2-git-send-email-tzanussi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 6c9aa16..8d05337 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -427,6 +427,25 @@
return err;
}
+int perf_header__write_pipe(int fd)
+{
+ struct perf_pipe_file_header f_header;
+ int err;
+
+ f_header = (struct perf_pipe_file_header){
+ .magic = PERF_MAGIC,
+ .size = sizeof(f_header),
+ };
+
+ err = do_write(fd, &f_header, sizeof(f_header));
+ if (err < 0) {
+ pr_debug("failed to write perf pipe header\n");
+ return err;
+ }
+
+ return 0;
+}
+
int perf_header__write(struct perf_header *self, int fd, bool at_exit)
{
struct perf_file_header f_header;
@@ -518,25 +537,10 @@
return 0;
}
-static int do_read(int fd, void *buf, size_t size)
-{
- while (size) {
- int ret = read(fd, buf, size);
-
- if (ret <= 0)
- return -1;
-
- size -= ret;
- buf += ret;
- }
-
- return 0;
-}
-
static int perf_header__getbuffer64(struct perf_header *self,
int fd, void *buf, size_t size)
{
- if (do_read(fd, buf, size))
+ if (do_read(fd, buf, size) <= 0)
return -1;
if (self->needs_swap)
@@ -592,7 +596,7 @@
{
lseek(fd, 0, SEEK_SET);
- if (do_read(fd, self, sizeof(*self)) ||
+ if (do_read(fd, self, sizeof(*self)) <= 0 ||
memcmp(&self->magic, __perf_magic, sizeof(self->magic)))
return -1;
@@ -662,13 +666,51 @@
return 0;
}
-int perf_header__read(struct perf_header *self, int fd)
+static int perf_file_header__read_pipe(struct perf_pipe_file_header *self,
+ struct perf_header *ph, int fd)
{
+ if (do_read(fd, self, sizeof(*self)) <= 0 ||
+ memcmp(&self->magic, __perf_magic, sizeof(self->magic)))
+ return -1;
+
+ if (self->size != sizeof(*self)) {
+ u64 size = bswap_64(self->size);
+
+ if (size != sizeof(*self))
+ return -1;
+
+ ph->needs_swap = true;
+ }
+
+ return 0;
+}
+
+static int perf_header__read_pipe(struct perf_session *session, int fd)
+{
+ struct perf_header *self = &session->header;
+ struct perf_pipe_file_header f_header;
+
+ if (perf_file_header__read_pipe(&f_header, self, fd) < 0) {
+ pr_debug("incompatible file format\n");
+ return -EINVAL;
+ }
+
+ session->fd = fd;
+
+ return 0;
+}
+
+int perf_header__read(struct perf_session *session, int fd)
+{
+ struct perf_header *self = &session->header;
struct perf_file_header f_header;
struct perf_file_attr f_attr;
u64 f_id;
int nr_attrs, nr_ids, i, j;
+ if (session->fd_pipe)
+ return perf_header__read_pipe(session, fd);
+
if (perf_file_header__read(&f_header, self, fd) < 0) {
pr_debug("incompatible file format\n");
return -EINVAL;