This is the mail archive of the
mailing list for the glibc project.
Re: Dummy pthread functions in libc considered harmful
- From: Florian Weimer <fweimer at redhat dot com>
- To: Alexander Monakov <amonakov at ispras dot ru>, OndÅej BÃlka <neleai at seznam dot cz>
- Cc: Rich Felker <dalias at libc dot org>, Samuel Thibault <samuel dot thibault at ens-lyon dot org>, Andreas Schwab <schwab at suse dot de>, libc-alpha at sourceware dot org
- Date: Tue, 25 Aug 2015 16:37:25 +0200
- Subject: Re: Dummy pthread functions in libc considered harmful
- Authentication-results: sourceware.org; auth=none
- References: <mvmr3ms4sbj dot fsf at hawking dot suse dot de> <20150824153816 dot GC3210 at type dot bordeaux dot inria dot fr> <20150824162250 dot GD32742 at brightrain dot aerifal dot cx> <20150825125035 dot GA3463 at domone> <alpine dot LNX dot 2 dot 20 dot 1508251557030 dot 18864 at monopod dot intra dot ispras dot ru>
On 08/25/2015 03:01 PM, Alexander Monakov wrote:
> On Tue, 25 Aug 2015, Ondřej Bílka wrote:
>> As we internally already have SINGLE_THREAD_P optimization we should use
>> that optimization for all atomics and locks and get slower path only
>> when there is some thread created.
>> We could export that variable for gcc to also speed up atomics.
> It's not possible to use "current process is single-threaded" predicate to
> optimize atomics: they might be operating on shared memory.
Such mutexes must be marked as process-shared, and therefore, the
optimization could be skipped for them, I think.
Florian Weimer / Red Hat Product Security