Message-ID: <55819AB3.9060308@gmail.com>
Date: Wed, 17 Jun 2015 10:05:07 -0600
From: David Ahern <dsahern@gmail.com>
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To: kan.liang@intel.com, acme@kernel.org
CC: linux-kernel@vger.kernel.org, ying.huang@intel.com, andi@firstfloor.org
Subject: Re: [PATCH V3 1/2] perf,tools: add time out to force stop proc map
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On 6/17/15 1:56 AM, kan.liang@intel.com wrote:
> diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
> index 793b150..ac6cf2a 100644
> --- a/tools/perf/util/event.c
> +++ b/tools/perf/util/event.c
> @@ -213,6 +213,8 @@ static int perf_event__synthesize_fork(struct perf_tool *tool,
>   	return 0;
>   }
>
> +#define MMAP_TIMEOUT	(50 * 1000000ULL)
> +

How did you determine 50msec is a good time? This seems really low to me 
considering the range of platforms supported by perf and various run 
time conditions. The default needs to work right on all platforms.

Why not have the default be infinity and users who need the feature use 
the option provided in patch 2?

David
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