[gentoo-dev] threads vs. smp

[gentoo-dev] threads vs. smp

[Hanno Böck]

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I got this bug and as I don't know if this is correct what the user says (no 
idea about smp), I'm posting this here for comments:

https://bugs.gentoo.org/show_bug.cgi?id=224729

cite bug report:
I added "threads" to make.conf a while ago on my SMP machine. Now i merged 
gimp
and found that it uses the flag "smp" for the same purpose. At least i think
its for the same purpose.
This is confusing and forces users to maintain local flags for same apps. I
would suggest that all ebuilds using the smp-flag switch to threads if there 
is no good reason to have a separate USE flag.
[...]
This is a recent list of ebuilds using the local flag "smp"

dev-lang/erlang/erlang-12.2.2.ebuild
games-fps/alephone/alephone-20071103.ebuild
media-gfx/gimp/gimp-2.3.19.ebuild
media-gfx/gimp/gimp-2.4.2.ebuild
media-gfx/gimp/gimp-2.4.5.ebuild
media-gfx/gimp/gimp-9999.ebuild
media-plugins/gimp-greycstoration/gimp-greycstoration-2.8.ebuild
sys-cluster/charm/charm-5.9.ebuild
sys-cluster/openmpi/openmpi-1.2.5.ebuild
sys-cluster/openmpi/openmpi-1.2.6.ebuild
-- 
Hanno Böck		Blog:   http://www.hboeck.de/
GPG: 3DBD3B20		Jabber: hanno@hboeck.de

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Re: [gentoo-dev] threads vs. smp

[Arun Raghavan]

On Sun, Jun 8, 2008 at 6:04 PM, Hanno Böck <hanno@gentoo.org> wrote:
> I got this bug and as I don't know if this is correct what the user says (no
> idea about smp), I'm posting this here for comments:
>
> https://bugs.gentoo.org/show_bug.cgi?id=224729

Looks like there are 3 possible uses of the threads/smp USE flags:

1) Add support for a threading API in a library/language (for example
in dev-lisp/sbcl)

2) Add support for threading in an application (www-servers/apache, for exmple)

3) Add support for a multi-processor machine -- this is different from
(2) in that the application doesn't really gain anything if this is
used on a uni-processor machine (sys-cluster/charm seems to fall in
this category)

I guess it would be consistent to use "threads" for (1) and (2), and
"smp" for (3).

Now, as for Gimp, grokking through the sources shows that "--with-mp"
basically lets some processing stuff run in separate threads. This is
clearly only useful on SMT/CMP/SMP machines, so I think USE=smp is
fine.

The user's complaint could be valid, though. Perhaps "smp" should be a
global USE flag.

Cheers,
-- 
Arun Raghavan
(http://nemesis.accosted.net)
v2sw5Chw4+5ln4pr6$OFck2ma4+9u8w3+1!m?l7+9GSCKi056
e6+9i4b8/9HTAen4+5g4/8APa2Xs8r1/2p5-8 hackerkey.com
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gentoo-dev@lists.gentoo.org mailing list

[gentoo-dev] Re: threads vs. smp

[Christian Faulhammer]

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Hi,

Hanno Böck <hanno@gentoo.org>:
> This is a recent list of ebuilds using the local flag "smp"
> 
> dev-lang/erlang/erlang-12.2.2.ebuild

 It is called SMP support in Erlang, and users will expect exactly that
tied to a smp USE flag.

V-Li


-- 
Christian Faulhammer, Gentoo Lisp project
<URL:http://www.gentoo.org/proj/en/lisp/>, #gentoo-lisp on FreeNode

<URL:http://www.faulhammer.org/>

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