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

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Message-ID: <39a1cf8d-2496-72f6-c3a4-a4abb8008689@linux.intel.com>
Date:   Wed, 20 Feb 2019 17:15:13 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/4] perf record: implement -z=<level> and
 --mmap-flush=<thres> options


On 12.02.2019 16:08, Jiri Olsa wrote:
> On Mon, Feb 11, 2019 at 11:22:38PM +0300, Alexey Budankov wrote:
> 
> SNIP
> 
>> -	if (rec->opts.nr_cblocks > nr_cblocks_max)
>> -		rec->opts.nr_cblocks = nr_cblocks_max;
>> -	if (verbose > 0)
>> -		pr_info("nr_cblocks: %d\n", rec->opts.nr_cblocks);
>> +	if (rec->opts.comp_level > 22)
>> +		rec->opts.comp_level = 0;
>> +	if (record__comp_enabled(rec) && !rec->opts.nr_cblocks) {
>> +		 /*
>> +		  * Allocate aio.data[0] buffer for compression.
>> +		  */
>> +		rec->opts.nr_cblocks = -1;
>> +	}
> 
> I assume you're using aio.data[0] as a buffer for non-aio case
> as compression buffer.. if that's the case, please dont do that
> and use separate buffer for that

Do you want it to be one more field in the mmap struct or 
aio related fields still could be reworked?

Thanks,
Alexey

> 
> jirka
>