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SubjectRe: [PATCH v2 2/4] perf record: implement -z=<level> and --mmap-flush=<thres> options
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On 20.02.2019 17:14, Alexey Budankov wrote:
>
> On 12.02.2019 16:09, Jiri Olsa wrote:
>> On Mon, Feb 11, 2019 at 11:22:38PM +0300, Alexey Budankov wrote:
>>
>> SNIP
>>
>>> @@ -1147,6 +1193,10 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>>> fd = perf_data__fd(data);
>>> rec->session = session;
>>>
>>> + rec->opts.comp_level = 0;
>>> + session->header.env.comp_level = rec->opts.comp_level;
>>> + session->header.env.comp_type = PERF_COMP_NONE;
>>> +
>>> record__init_features(rec);
>>>
>>> if (rec->opts.use_clockid && rec->opts.clockid_res_ns)
>>> @@ -1176,6 +1226,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>>> err = -1;
>>> goto out_child;
>>> }
>>> + session->header.env.comp_mmap_len = session->evlist->mmap_len;
>>
>> so the comp_mmap_len is the max length of the compressed packet?
>
> comp_mmap_len is the size of buffer to encompass one compressed chunk
> of data after its decompression.
>
>>
>> any idea if this value might have some impact on the processing speed?
>
> It increases memory consumption at the loading and processing stages.
>
>>
>> I see you mentioned the size reduction, could you also meassure
>> the record overhead?
>
> Let's get back to this after the code review.

Overhead numbers are provided in v3.

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

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