lkml.org 
[lkml]   [2018]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v12 2/3]: perf record: enable asynchronous trace writing
On Tue, Oct 09, 2018 at 11:58:53AM +0300, Alexey Budankov wrote:

SNIP

> +#ifdef HAVE_AIO_SUPPORT
> +int perf_mmap__aio_push(struct perf_mmap *md, void *to,
> + int push(void *to, struct aiocb *cblock, void *buf, size_t size, off_t off),
> + off_t *off)
> +{
> + u64 head = perf_mmap__read_head(md);
> + unsigned char *data = md->base + page_size;
> + unsigned long size, size0 = 0;
> + void *buf;
> + int rc = 0;
> +
> + rc = perf_mmap__read_init(md);
> + if (rc < 0)
> + return (rc == -EAGAIN) ? 0 : -1;
> +
> + /*
> + * md->base data is copied into md->data buffer to
> + * release space in the kernel buffer as fast as possible,
> + * thru perf_mmap__consume() below.
> + *
> + * That lets the kernel to proceed with storing more
> + * profiling data into the kernel buffer earlier than other
> + * per-cpu kernel buffers are handled.
> + *
> + * Coping can be done in two steps in case the chunk of
> + * profiling data crosses the upper bound of the kernel buffer.
> + * In this case we first move part of data from md->start
> + * till the upper bound and then the reminder from the
> + * beginning of the kernel buffer till the end of
> + * the data chunk.
> + */
> +
> + size = md->end - md->start;
> +
> + if ((md->start & md->mask) + size != (md->end & md->mask)) {
> + buf = &data[md->start & md->mask];
> + size = md->mask + 1 - (md->start & md->mask);
> + md->start += size;
> + memcpy(md->aio.data, buf, size);
> + size0 = size;
> + }
> +
> + buf = &data[md->start & md->mask];
> + size = md->end - md->start;
> + md->start += size;
> + memcpy(md->aio.data + size0, buf, size);
> +
> + /*
> + * Increment md->refcount to guard md->data buffer
> + * from premature deallocation because md object can be
> + * released earlier than aio write request started
> + * on mmap->data is complete.
> + *
> + * perf_mmap__put() is done at record__aio_complete()
> + * after started request completion.
> + */
> + perf_mmap__get(md);
> +
> + md->prev = head;
> + perf_mmap__consume(md);
> +
> + rc = push(to, &(md->aio.cblock), md->aio.data, size0 + size, *off);
> + if (!rc) {
> + *off += size0 + size;
> + } else {
> + /*
> + * Decrement md->refcount back if aio write
> + * operation failed to start.
> + */
> + perf_mmap__put(md);
> + }
> +
> + return rc;
> +}
> +#else
> +int perf_mmap__aio_push(struct perf_mmap *md __maybe_unused, void *to __maybe_unused,
> + int push(void *to, struct aiocb *cblock, void *buf, size_t size, off_t off) __maybe_unused,
> + off_t *off __maybe_unused)
> +{
> + return 0;
> +}

I think you need to put this one in the header as static inline
otherwise it'd still appear in the NO_AIO=1 build, like:
[jolsa@krava perf]$ make NO_AIO=1
...
[jolsa@krava perf]$ nm -D perf | grep perf_mmap__aio_push
00000000004c2be0 T perf_mmap__aio_push

change below makes it disappear completely

jirka


---
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index b176d88b3fcb..8c7516696891 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -445,13 +445,6 @@ int perf_mmap__aio_push(struct perf_mmap *md, void *to,

return rc;
}
-#else
-int perf_mmap__aio_push(struct perf_mmap *md __maybe_unused, void *to __maybe_unused,
- int push(void *to, struct aiocb *cblock, void *buf, size_t size, off_t off) __maybe_unused,
- off_t *off __maybe_unused)
-{
- return 0;
-}
#endif

/*
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index 04ff4d2ffdbe..3ccf8c925002 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -105,10 +105,21 @@ union perf_event *perf_mmap__read_event(struct perf_mmap *map);

int perf_mmap__push(struct perf_mmap *md, void *to,
int push(struct perf_mmap *map, void *to, void *buf, size_t size));
+
+#ifdef HAVE_AIO_SUPPORT
int perf_mmap__aio_push(struct perf_mmap *md, void *to,
int push(void *to, struct aiocb *cblock, void *buf, size_t size, off_t off),
off_t *off);

+#else
+static inline int perf_mmap__aio_push(struct perf_mmap *md __maybe_unused, void *to __maybe_unused,
+ int push(void *to, struct aiocb *cblock, void *buf, size_t size, off_t off) __maybe_unused,
+ off_t *off __maybe_unused)
+{
+ return 0;
+}
+#endif
+
size_t perf_mmap__mmap_len(struct perf_mmap *map);

int perf_mmap__read_init(struct perf_mmap *md);
\
 
 \ /
  Last update: 2018-10-11 15:47    [W:0.142 / U:8.644 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site