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

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Message-ID: <20190212130828.GD775@krava>
Date:   Tue, 12 Feb 2019 14:08:28 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.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 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

jirka