Re: [PATCH] msleep() with hrtimers

On Mon, 7 Jan 2008 13:38:08 -0800
David Brownell <[email protected]> wrote:

> On Thursday 09 August 2007, Andrew Morton wrote:
> > On Fri, 03 Aug 2007 12:37:12 -0600 Jonathan Corbet <[email protected]> wrote:
> > 
> > > Here's the second (and probably final) posting of the msleep() with
> > > hrtimers patch.  The problem being addressed here is that the current
> > > msleep() will stop for a minimum of two jiffies, meaning that, on a
> > > HZ=100 system, msleep(1) delays for for about 20ms.  In a driver with
> > > one such delay for each of 150 or so register setting operations, the
> > > extra time adds up to a few seconds.
> > > 
> > > This patch addresses the situation by using hrtimers.  On tickless
> > > systems with working timers, msleep(1) now sleeps for 1ms, even with
> > > HZ=100.
> 
> For what it's worth, I've been using this on a variety of systems since
> August, without even one observed problem.  I rather like the idea of
> an msleep() that really does what it claims to do, instead of wasting
> extra time!
> 
> 
> > >			...
> > 
> > This failed the Vaio test.  I guess it triggered a USB bug.
> 
> Does it still fail?

It did on 28 Nov: http://lkml.org/lkml/2007/11/28/65

> If there was followup to the "what do the logs show with CONFIG_USB_DEBUG"
> response, I didn't see it.

Sigh.  Will add it to the todo list (after the 852 emails in my to-apply
folder) but I'll probably need reminding.


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