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Re: Consensus: Tuning runtime behaviour with environment variables.
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: OndÅej BÃlka <neleai at seznam dot cz>
- Cc: KOSAKI Motohiro <kosaki dot motohiro at gmail dot com>, libc-alpha at sourceware dot org
- Date: Thu, 30 May 2013 10:49:09 -0400
- Subject: Re: Consensus: Tuning runtime behaviour with environment variables.
- References: <51A58A92 dot 4050508 at redhat dot com> <51A653DC dot 4040702 at gmail dot com> <20130529215955 dot GA31500 at domone dot kolej dot mff dot cuni dot cz> <51A67E6C dot 8020504 at redhat dot com> <20130530054346 dot GA1107 at domone dot kolej dot mff dot cuni dot cz>
On 05/30/2013 01:43 AM, OndÅej BÃlka wrote:
> On Wed, May 29, 2013 at 06:17:16PM -0400, Carlos O'Donell wrote:
>> On 05/29/2013 05:59 PM, OndÅej BÃlka wrote:
>>> Needs comment that changing runtime behaviour by setting its setenv is
>>> not supported(Unless we add small performance penalty for each setenv).
>>
>> No, using setenv will never change the behaviour once the process
>> is started. At that point your only option would be a new API that
>> exposes tunables in a thread-safe way with explicitly defined
>> semantics.
>>
> Well I meant exactly that and that you need add this to user
> documentation.
Agreed. Thanks for the clarification.
The text for env var support reads:
"Changing any of the env vars that control runtime tuning will have no
effect on the currently executing process."
http://sourceware.org/glibc/wiki/TuningLibraryRuntimeBehavior
Cheers,
Carlos.