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Re: gcc 4.1 implements compiler builtins for atomic ops
- From: Benjamin Herrenschmidt <benh at kernel dot crashing dot org>
- To: "Carlos O'Donell" <carlos at systemhalted dot org>
- Cc: Anuj Goyal <anuj dot goyal at gmail dot com>, hollis at penguinppc dot org, libc-alpha at sources dot redhat dot com, roland at redhat dot com
- Date: Mon, 27 Jun 2005 08:50:33 +1000
- Subject: Re: gcc 4.1 implements compiler builtins for atomic ops
- References: <2f225d01050625091875932e04@mail.gmail.com> <7a02832e219e2e6ceca78f06264d7a94@penguinppc.org> <1119742835.5133.12.camel@gaston> <2f225d0105062519451d9e9c85@mail.gmail.com> <20050626212926.GC5269@systemhalted.org>
> We will be working to implement the atomic ops in gcc on parisc.
>
> For parisc the atomic operation is implemented as a light-weight
> syscall, on the gateway page, consisting of 18 instructions on the fast
> path. Tests show this is as close to optimal as possible. With scaling
> out to ~16 cpus (all on paper though). I could probably re-architect the
> light-weight-syscall locking to scale to higher cpus.
>
> This has the unfortunate issue of requiring a newer kernel. I'm not sure
> how to handle this type of requirement against gcc. With glibc I could
> use a vDSO or --enable-kernel and some package management entries.
So you are putting vDSO dependencies in gcc ? ugh ?
Am I the only one to think that this is a very bad idea ?
Damn, these things should be in glibc, not the compiler !
Ben.