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SubjectRe: [PATCH v2 2/4] perf record: implement -z=<level> and --mmap-flush=<thres> options
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On 12.02.2019 16:08, Jiri Olsa wrote:
> On Mon, Feb 11, 2019 at 11:22:38PM +0300, Alexey Budankov wrote:
>
> SNIP
>
>> +static int perf_mmap__aio_mmap_blocks(struct perf_mmap *map);
>> +
>> static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp)
>> {
>> - int delta_max, i, prio, ret;
>> + int i, ret = 0, init_blocks = 1;
>>
>> map->aio.nr_cblocks = mp->nr_cblocks;
>> + if (map->aio.nr_cblocks == -1) {
>> + map->aio.nr_cblocks = 1;
>> + init_blocks = 0;
>> + }
>> +
>> if (map->aio.nr_cblocks) {
>> - map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *));
>> - if (!map->aio.aiocb) {
>> - pr_debug2("failed to allocate aiocb for data buffer, error %m\n");
>> - return -1;
>> - }
>> - map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb));
>> - if (!map->aio.cblocks) {
>> - pr_debug2("failed to allocate cblocks for data buffer, error %m\n");
>> - return -1;
>> - }
>> map->aio.data = calloc(map->aio.nr_cblocks, sizeof(void *));
>> if (!map->aio.data) {
>> pr_debug2("failed to allocate data buffer, error %m\n");
>> return -1;
>> }
>> - delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
>> for (i = 0; i < map->aio.nr_cblocks; ++i) {
>> ret = perf_mmap__aio_alloc(map, i);
>> if (ret == -1) {
>> @@ -251,29 +245,16 @@ static int perf_mmap__aio_mmap(struct perf_mmap *map, struct mmap_params *mp)
>> ret = perf_mmap__aio_bind(map, i, map->cpu, mp->affinity);
>> if (ret == -1)
>> return -1;
>> - /*
>> - * Use cblock.aio_fildes value different from -1
>> - * to denote started aio write operation on the
>> - * cblock so it requires explicit record__aio_sync()
>> - * call prior the cblock may be reused again.
>> - */
>> - map->aio.cblocks[i].aio_fildes = -1;
>> - /*
>> - * Allocate cblocks with priority delta to have
>> - * faster aio write system calls because queued requests
>> - * are kept in separate per-prio queues and adding
>> - * a new request will iterate thru shorter per-prio
>> - * list. Blocks with numbers higher than
>> - * _SC_AIO_PRIO_DELTA_MAX go with priority 0.
>> - */
>> - prio = delta_max - i;
>> - map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0;
>> }
>> + if (init_blocks)
>> + ret = perf_mmap__aio_mmap_blocks(map);
>> }
>>
>> - return 0;
>> + return ret;
>> }
>
> SNIP
>
> it seems like little refactoring happened in here (up and down) for
> aio code, which is not explained and I'm unable to follow it.. please
> separate this in simple change

AIO buffers management has been taken out of HAVE_AIO_SUPPORT define
to be used for compression in case of serial streaming. It will be
revisited after other issues are addressed.

Thanks,
Alexey

>
> SNIP
>
>> +#ifdef HAVE_AIO_SUPPORT
>> +static int perf_mmap__aio_mmap_blocks(struct perf_mmap *map)
>> +{
>> + int delta_max, i, prio;
>> +
>> + map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *));
>> + if (!map->aio.aiocb) {
>> + pr_debug2("failed to allocate aiocb for data buffer, error %m\n");
>> + return -1;
>> + }
>> + map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb));
>> + if (!map->aio.cblocks) {
>> + pr_debug2("failed to allocate cblocks for data buffer, error %m\n");
>> + return -1;
>> + }
>> + delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
>> + for (i = 0; i < map->aio.nr_cblocks; ++i) {
>> + /*
>> + * Use cblock.aio_fildes value different from -1
>> + * to denote started aio write operation on the
>> + * cblock so it requires explicit record__aio_sync()
>> + * call prior the cblock may be reused again.
>> + */
>> + map->aio.cblocks[i].aio_fildes = -1;
>> + /*
>> + * Allocate cblocks with priority delta to have
>> + * faster aio write system calls because queued requests
>> + * are kept in separate per-prio queues and adding
>> + * a new request will iterate thru shorter per-prio
>> + * list. Blocks with numbers higher than
>> + * _SC_AIO_PRIO_DELTA_MAX go with priority 0.
>> + */
>> + prio = delta_max - i;
>> + map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0;
>> + }
>> +
>> + return 0;
>> +}
>> +
>
> SNIP
>

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