[quagga-dev 7442] Re: (no subject)

Stephen Hemminger shemminger at vyatta.com
Mon Nov 30 19:43:51 GMT 2009


On Mon, 30 Nov 2009 19:22:09 +0100
Joakim Tjernlund <joakim.tjernlund at transmode.se> wrote:

> >
> > On 30/11/2009 17:21, Joakim Tjernlund wrote:
> > > linux 2.4 is still in use today because it is much smaller.
> >
> > Does the sort of glibc that you would use on a linux 2.4 support pthreads?
> 
> Yes, but not NPTL
> 
> >
> > let me rephrase: does it support pthreads in a way which is bug-fix
> > compatible with current versions of glibc or other libcs which are in use
> > on more modern versions of linux?
> >
> > As another important issue to add to Greg's questions: how inter-compatible
> > are the various pthread implementations used by the various operating
> > systems that quagga supports?
> 
> No idea, but as far as MONOTONIC_CLOCK goes, one should use times(2) when it
> is missing.
> 
> Threads is different issue, I don't think anyone wants to use pthreads on older
> linux so no need to try. Just make sure the current "threads" still works after
> you have added NPTL support.
> 

Unfortunately, pthread mutex and locking primitives are slow. That is why almost
all the databases end up rolling their own. Part of the problem is the glibc clash
between being portable and being fast.

What is the proposed design for using threads? I am concerned that if it just changes
the bottleneck from being a single thread, to having a single lock there will be
little performance gain.



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