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

[Jiri Olsa <jolsa@redhat.com>]

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?

any idea if this value might have some impact on the processing speed?

I see you mentioned the size reduction, could you also meassure
the record overhead?

thanks,
jirka