[PATCH v3 11/15] perf header: add a buffer to struct feat_fd

David Carrillo-Cisneros
2017-06-06T07:08:08Z

Extend struct feat_fd to use a temporal buffer in pipe-mode, instead
of perf.data's file descriptor.

The header features build_id and aux_trace already have logic to
print in file-mode that heavily rely on lseek the file. For now, leave
such features inactive in pipe-mode and print a warning if their
functions are called in pipe-mode.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
---
tools/perf/util/header.c | 83 +++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 72 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 323ccd5df382..109675b35fab 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -61,6 +61,7 @@ struct perf_file_attr {
struct feat_fd {
struct perf_header *ph;
int fd;
+ void *buf; /* Either buf != NULL or fd >= 0 */
ssize_t offset;
size_t size;
};
@@ -80,18 +81,43 @@ bool perf_header__has_feat(const struct perf_header *header, int feat)
return test_bit(feat, header->adds_features);
}

-/* Return: 0 if succeded, -ERR if failed. */
-int do_write(struct feat_fd *ff, const void *buf, size_t size)
+static int __do_write_fd(struct feat_fd *ff, const void *buf, size_t size)
{
- ssize_t ret;
+ ssize_t ret = writen(ff->fd, buf, size);

- ret = writen(ff->fd, buf, size);
if (ret != (ssize_t)size)
- return ret < 0 ? (int)ret: -1;
+ return ret < 0 ? (int)ret : -1;
+ return 0;
+}
+
+static int __do_write_buf(struct feat_fd *ff, const void *buf, size_t size)
+{
+ void *addr;
+
+retry:
+ if (size > (ff->size - ff->offset)) {
+ addr = realloc(ff->buf, ff->size << 1);
+ if (!addr)
+ return -ENOSPC;
+ ff->buf = addr;
+ ff->size <<= 1;
+ goto retry;
+ }
+
+ memcpy(ff->buf + ff->offset, buf, size);
+ ff->offset += size;

return 0;
}

+/* Return: 0 if succeded, -ERR if failed. */
+int do_write(struct feat_fd *ff, const void *buf, size_t size)
+{
+ if (!ff->buf)
+ return __do_write_fd(ff, buf, size);
+ return __do_write_buf(ff, buf, size);
+}
+
/* Return: 0 if succeded, -ERR if failed. */
int write_padded(struct feat_fd *ff, const void *bf,
size_t count, size_t count_aligned)
@@ -125,13 +151,32 @@ static int do_write_string(struct feat_fd *ff, const char *str)
return write_padded(ff, str, olen, len);
}

-static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
+static int __do_read_fd(struct feat_fd *ff, void *addr, ssize_t size)
{
- ssize_t ret = readn(ff->fd, addr, size);
+ ssize_t ret = readn(ff->fd, addr, size);
+
+ if (ret != size)
+ return ret < 0 ? (int)ret : -1;
+ return 0;
+}
+
+static int __do_read_buf(struct feat_fd *ff, void *addr, ssize_t size)
+{
+ if (size > (ssize_t)ff->size - ff->offset)
+ return -1;
+
+ memcpy(addr, ff->buf + ff->offset, size);
+ ff->offset += size;

- if (ret != size)
- return ret < 0 ? (int)ret : -1;
return 0;
+
+}
+
+static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
+{
+ if (!ff->buf)
+ return __do_read_fd(ff, addr, size);
+ return __do_read_buf(ff, addr, size);
}

static int do_read_u32(struct feat_fd *ff, u32 *addr)
@@ -188,6 +233,10 @@ static char *do_read_string(struct feat_fd *ff)
static int write_tracing_data(struct feat_fd *ff,
struct perf_evlist *evlist)
{
+ if (ff->buf) {
+ WARN_ON("Pipe-mode doesn't supported write_tracing_data.\n");
+ return -1;
+ }
return read_tracing_data(ff->fd, &evlist->entries);
}

@@ -202,6 +251,10 @@ static int write_build_id(struct feat_fd *ff,
if (!perf_session__read_build_ids(session, true))
return -1;

+ if (ff->buf) {
+ WARN_ON("Pipe-mode doesn't support write_build_id.\n");
+ return -1;
+ }
err = perf_session__write_buildid_table(session, ff);
if (err < 0) {
pr_debug("failed to write buildid table\n");
@@ -911,6 +964,10 @@ static int write_auxtrace(struct feat_fd *ff,
struct perf_session *session;
int err;

+ if (ff->buf) {
+ pr_err("Unsupported write_auxtrace to memory buffer.\n");
+ return -1;
+ }
session = container_of(ff->ph, struct perf_session, header);

err = auxtrace_index__write(ff->fd, &session->auxtrace_index);
@@ -2192,6 +2249,10 @@ static int do_write_feat(struct feat_fd *ff, int type,
if (!feat_ops[type].write)
return -1;

+ if (ff->buf) {
+ pr_err("Called %s for memory buffer.\n", __func__);
+ return -1;
+ }
(*p)->offset = lseek(ff->fd, 0, SEEK_CUR);

err = feat_ops[type].write(ff, evlist);
@@ -2600,7 +2661,7 @@ static int perf_file_section__process(struct perf_file_section *section,
struct perf_header *ph,
int feat, int fd, void *data)
{
- struct feat_fd fdd = {
+ struct feat_fd ff = {
.fd = fd,
.ph = ph,
.size = section->size,
@@ -2621,7 +2682,7 @@ static int perf_file_section__process(struct perf_file_section *section,
if (!feat_ops[feat].process)
return 0;

- return feat_ops[feat].process(&fdd, data);
+ return feat_ops[feat].process(&ff, data);
}

static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,