AW: LinuxThreads replacement

[Kai Mosebach]

Hi,

Hmm, some kind of benchmark would be pretty interesting, thats right.
But im not sure, whether its done by simply switching between the lib in
the
Libmap.conf, because sapdb consists of ~50 executables, which are
startet from each other (for example, you have a service listener, which
starts a dm-manager, and later on a database-kernel and so on ...), so i
guess, that i have to whether 1) link libc_r or some nasty trick like
that, or to create to binary versions.

cheers

-----Ursprüngliche Nachricht-----
Von: Mike Makonnen [mailto:mtm at identd.net] 
Gesendet: Donnerstag, 10. Juli 2003 02:12
An: Petri Helenius
Cc: Kai Mosebach; freebsd-threads at freebsd.org
Betreff: Re: LinuxThreads replacement

On Wed, Jul 09, 2003 at 10:11:15PM +0300, Petri Helenius wrote:
> >for example, for on database instance, there are about 80 (lthread)
> >processes hanging around.
> 
> I would say with 80 threads you?ll get better performance with libkse
> since you?ll get less contention on the process scheduler.
> 

It's not as simple as that. In practice a lot of factors about
your system and the type of work you're doing will affect the
performance. On paper, the SA/KSE method is supposed to combine
the best aspects of 1:1 (libthr) and N:1 (libc_r), and should
threoretically be "better" than either one. But, in practice,
complexity and overhead may drown out the performance gains.
Conversely, context switching overhead may not be as great a
penalty for the 1:1 model on modern cpus.

I don't want to get in a flamewar over this. I just wanted to point
out that it's not as simple as "contention on the process
scheduler." I think what we need, now that both libthr and libkse
are somewhat useable, is some benchmarking comparisons.

If you have the time I think we would all be interested to see
any performance comparisons you can run with your application.
Once you compile the application switching threads libraries is as
simple as editing /etc/libmap.conf.


Cheers.
-- 
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