linux-kernel - Re: tickless and HZ=1000 throughput advantage?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Sun, 20 Sep 2009 09:40:22 +0200
From:	Arjan van de Ven <arjan@...radead.org>
To:	Tim Blechmann <tim@...ngt.org>
Cc:	linux-kernel@...r.kernel.org,
	Daniel J Blueman <daniel.blueman@...il.com>
Subject: Re: tickless and HZ=1000 throughput advantage?

On Sun, 20 Sep 2009 09:34:30 +0200
Tim Blechmann <tim@...ngt.org> wrote:

> On 09/20/2009 01:12 AM, Ben Nizette wrote:
> > On Sat, 2009-09-19 at 18:50 +0100, Daniel J Blueman wrote:
> > 
> >> Agreed. Do you think there is still a small case for moving to
> >> HZ=1000 (given it's effectively free) in situations like:
> > 
> > Sure HZ=1000 gives you more accurate sleeps, that's kind of the
> > point, but since when has it been "effectively free"?
> > http://lwn.net/Articles/331607/
> 
> i'd be curious, what effect does it have on userspace applications?
> like, does it effect the wakeup latency of userspace (pthread)
> mutexes/conditions or posix semaphores?

the impact to userspace should be zero nowadays since select/poll/etc
moved to hrtimers, which are HZ-independent.



-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/