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From: Florian Weimer <fw@deneb.enyo.de>
To: Rich Felker <dalias@libc.org>
Cc: musl@lists.openwall.com,  Norbert Lange <nolange79@gmail.com>
References: <CADYdroOZ__aFuCCBWCAOBRcH==0W-NUKH423biu217X9t6Pxeg@mail.gmail.com>
	<20200409181824.GD13749@port70.net> <87r1wwik8t.fsf@mid.deneb.enyo.de>
	<20200410010255.GN11469@brightrain.aerifal.cx>
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	<20200414155522.GB11469@brightrain.aerifal.cx>
Date: Tue, 14 Apr 2020 18:55:06 +0200
In-Reply-To: <20200414155522.GB11469@brightrain.aerifal.cx> (Rich Felker's
	message of "Tue, 14 Apr 2020 11:55:22 -0400")
Message-ID: <87wo6iknx1.fsf@mid.deneb.enyo.de>
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Subject: Re: [musl] [BUG] sysconf implementing _SC_NPROCESSORS_(CONF|ONLN) incorrectly

* Rich Felker:

> On Tue, Apr 14, 2020 at 12:08:52PM +0200, Florian Weimer wrote:
>> * Rich Felker:
>> 
>> >> For glibc, we had to change our logic to artificially inflate the CPU
>> >> to 2 if we cannot determine it, as the more conservative choice.
>> >
>> > Wait, you mean some software is abusing these interfaces to omit
>> > memory barriers or something? *facepalm* *sigh*
>> 
>> Yes, indeed.  glibc itself parses uname -v output for this purpose
>> (something we should probably remove, too).
>
> I don't understand. Certainly it's not executing a child process at
> runtime. Do you mean SYS_uname or are you talking about guessing
> number of cpus for parallel build at make time or something?

I meant the string that is printed by uname -v.  The internal
implementation is of course different.