Re: [PATCH] perf record: Add snapshot mode support for perf's regular events
From: David Ahern
Date: Tue Nov 24 2015 - 10:24:14 EST
On 11/24/15 8:20 AM, Arnaldo Carvalho de Melo wrote:
Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
On 11/24/15 7:00 AM, Yunlong Song wrote:
+static int record__write(struct record *rec, void *bf, size_t size)
+{
+ if (rec->memory.size && memory_enabled) {
+ if (perf_memory__write(&rec->memory, bf, size) < 0) {
+ pr_err("failed to write memory data, error: %m\n");
+ return -1;
+ }
+ } else {
+ if (perf_data_file__write(rec->session->file, bf, size) < 0) {
+ pr_err("failed to write perf data, error: %m\n");
+ return -1;
+ }
+ rec->bytes_written += size;
}
- rec->bytes_written += size;
return 0;
}
@@ -86,6 +214,8 @@ static int record__mmap_read(struct record *rec, int idx)
if (old == head)
return 0;
+ memory_enabled = 1;
+
rec->samples++;
size = head - old;
@@ -113,6 +243,7 @@ static int record__mmap_read(struct record *rec, int idx)
md->prev = old;
perf_evlist__mmap_consume(rec->evlist, idx);
out:
+ memory_enabled = 0;
return rc;
}
So you are basically ignoring all samples until SIGUSR2 is received. That
No, he is not, its just that his code is difficult to follow, has to be
rewritten, but he is ignoring just PERF_RECORD_SAMPLE events, so it
will..
means the resulting data file will have limited history of task events for
... have a complete history of task events, since PERF_RECORD_FORK, etc
are not being ignored.
No?
perf-record does not process events, it only writes to a file. If that
is skipped then it skips all events regardless of type.
David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/