Messages in this thread | | | Date | Wed, 9 Jan 2019 17:49:15 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH v2 2/4] perf record: bind the AIO user space buffers to nodes |
| |
On Wed, Jan 09, 2019 at 12:12:37PM +0300, Alexey Budankov wrote: > Hi, > > On 02.01.2019 0:41, Jiri Olsa wrote: > > On Mon, Dec 24, 2018 at 03:24:36PM +0300, Alexey Budankov wrote: > > > > SNIP > > > >> +static void perf_mmap__aio_free(void **data, size_t len __maybe_unused) > >> +{ > >> + zfree(data); > >> +} > >> + > >> +static void perf_mmap__aio_bind(void *data __maybe_unused, size_t len __maybe_unused, > >> + int cpu __maybe_unused, int affinity __maybe_unused) > >> +{ > >> +} > >> +#endif > >> + > >> static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp) > >> { > >> int delta_max, i, prio; > >> @@ -177,11 +220,13 @@ static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp) > >> } > >> delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX); > >> for (i = 0; i < map->aio.nr_cblocks; ++i) { > >> - map->aio.data[i] = malloc(perf_mmap__mmap_len(map)); > >> + size_t mmap_len = perf_mmap__mmap_len(map); > >> + perf_mmap__aio_alloc(&(map->aio.data[i]), mmap_len); > >> if (!map->aio.data[i]) { > >> pr_debug2("failed to allocate data buffer area, error %m"); > >> return -1; > >> } > >> + perf_mmap__aio_bind(map->aio.data[i], mmap_len, map->cpu, mp->affinity); > > > > this all does not work if bind fails.. I think we need to > > propagate the error value here and fail > > Proceeding further from this point still makes sense because > the buffer is available for operations and thread migration > alone can bring performance benefits. So the error is not fatal > and an explicit warning is implemented in v3. If you still think > it is better to propagate error from here it can be implemented.
so if that fails that the aio buffers won't be bound to node, while mmaps are, so I guess the speedup is from there?
if I use:
# perf record --aio --affinity=node
and see: "failed to bind..."
I can still see the benefit..? I guess the warning is ok then, another option seems confusing
jirka
| |