guile-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Locks and threads


From: Neil Jerram
Subject: Re: Locks and threads
Date: Wed, 25 Mar 2009 22:13:55 +0000
User-agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux)

Linas Vepstas <address@hidden> writes:

> Well, once you identify the section that needs locking,
> you'll want to use an rwlock instead of a mutex.  The
> rwlock (pthread_rwlock_rdlock) allows multiple
> simultaneous readers.  The writers, however, get
> exclusive access. (pthread_rwlock_wrlock)

I forgot to comment on this before...

In my view the important case to optimize is the one with only a
single thread - i.e. I don't want to add any significant performance
penalty in that case.  And for that case, IIUC, there is no difference
between a mutex and an rwlock.

Also I would guess that we would hit more portability issues in future
with a rwlock than with a mutex.  Of course, we could look at
configure time for rwlock support, and fall back to a mutex - but that
has a cost too, in code complexity.

On balance, therefore, I don't think using a rwlock rather than a
mutex is worthwhile.

Regards,
        Neil




reply via email to

[Prev in Thread] Current Thread [Next in Thread]