Re: [PATCH v2 2/4] perf record: implement -z=<level> and --mmap-flush=<thres> options

From: Alexey Budankov
Date: Mon Feb 25 2019 - 10:27:15 EST



On 21.02.2019 14:24, Alexey Budankov wrote:
>
> On 21.02.2019 12:49, Jiri Olsa wrote:
>> On Wed, Feb 20, 2019 at 06:24:30PM +0300, Alexey Budankov wrote:
>>>
>>> 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.
>>
>> as I said earlier, please separate this from aio
>
> Ok.

Addressed.

>
> Thanks,
> Alexey
>
>
>>
>> jirka
>>
>