Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional adaptive spinning | KernelTrap

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional adaptive spinning

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From: Peter Zijlstra

Subject: Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional adaptive spinning

Date: Tuesday, April 6, 2010 - 7:09 am

On Tue, 2010-04-06 at 16:41 +0300, Avi Kivity wrote:
quoted text> On 04/06/2010 04:35 PM, Peter Zijlstra wrote:
> > On Tue, 2010-04-06 at 16:28 +0300, Avi Kivity wrote:
> >    
> >> Yes, but that's the best case for spinning.  You could simply use a
> >> userspace spinlock in this case.
> >>      
> > Userspace spinlocks are evil.. they should _never_ be used.
> >    
> 
> But in this case they're fastest.  If we don't provide a non-evil 
> alternative, people will use them.
> 

That's what FUTEX_LOCK is about.

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Messages in current thread:

[PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional adapti ..., Darren Hart, (Mon Apr 5, 1:23 pm)

[PATCH 1/6] futex: replace fshared and clockrt with combin ..., Darren Hart, (Mon Apr 5, 1:23 pm)

[PATCH 2/6] futex: add futex_q static initializer, Darren Hart, (Mon Apr 5, 1:23 pm)

[PATCH 3/6] futex: refactor futex_lock_pi_atomic, Darren Hart, (Mon Apr 5, 1:23 pm)

[PATCH 4/6] futex: Add FUTEX_LOCK with optional adaptive s ..., Darren Hart, (Mon Apr 5, 1:23 pm)

[PATCH 5/6] futex: handle timeout inside adaptive lock spin, Darren Hart, (Mon Apr 5, 1:23 pm)

[PATCH 6/6] futex: Add aggressive adaptive spinning argume ..., Darren Hart, (Mon Apr 5, 1:23 pm)

Re: [PATCH V2^W V4 0/6][RFC] futex: FUTEX_LOCK with option ..., Darren Hart, (Mon Apr 5, 1:48 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Avi Kivity, (Mon Apr 5, 2:15 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Darren Hart, (Mon Apr 5, 2:54 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Avi Kivity, (Mon Apr 5, 3:21 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Darren Hart, (Mon Apr 5, 3:59 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Darren Hart, (Mon Apr 5, 4:15 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Chris Wright, (Mon Apr 5, 4:29 pm)

Re: [PATCH 5/6] futex: handle timeout inside adaptive lock ..., Thomas Gleixner, (Tue Apr 6, 1:27 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Peter Zijlstra, (Tue Apr 6, 1:48 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Avi Kivity, (Tue Apr 6, 6:28 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Avi Kivity, (Tue Apr 6, 6:30 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Peter Zijlstra, (Tue Apr 6, 6:35 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Avi Kivity, (Tue Apr 6, 6:41 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Alan Cox, (Tue Apr 6, 6:51 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Peter Zijlstra, (Tue Apr 6, 7:09 am)

[No subject], Ulrich Drepper, (Tue Apr 6, 7:47 am)

[No subject], Peter Zijlstra, (Tue Apr 6, 7:51 am)

[No subject], Darren Hart, (Tue Apr 6, 8:28 am)

[No subject], Peter Zijlstra, (Tue Apr 6, 8:29 am)

[No subject], Darren Hart, (Tue Apr 6, 8:33 am)

[No subject], Peter Zijlstra, (Tue Apr 6, 8:37 am)

[No subject], Avi Kivity, (Tue Apr 6, 9:06 am)

[No subject], Avi Kivity, (Tue Apr 6, 9:10 am)

[No subject], Thomas Gleixner, (Tue Apr 6, 9:14 am)

[No subject], Avi Kivity, (Tue Apr 6, 9:20 am)

[No subject], Alan Cox, (Tue Apr 6, 9:44 am)

[No subject], Alan Cox, (Tue Apr 6, 9:53 am)

[No subject], Alan Cox, (Tue Apr 6, 9:54 am)

[No subject], Thomas Gleixner, (Tue Apr 6, 9:55 am)

[No subject], Ulrich Drepper, (Tue Apr 6, 10:34 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Thomas Gleixner, (Tue Apr 6, 11:15 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Thomas Gleixner, (Tue Apr 6, 12:31 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Ulrich Drepper, (Tue Apr 6, 1:02 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Darren Hart, (Tue Apr 6, 2:22 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Thomas Gleixner, (Tue Apr 6, 4:16 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Darren Hart, (Tue Apr 6, 4:36 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Avi Kivity, (Tue Apr 6, 10:33 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., john cooper, (Tue Apr 6, 11:18 pm)

Re: [PATCH 4/6] futex: Add FUTEX_LOCK with optional adapti ..., Darren Hart, (Wed Apr 7, 10:26 am)

Re: [PATCH 5/6] futex: handle timeout inside adaptive lock ..., Darren Hart, (Wed Apr 7, 10:31 am)

Re: [PATCH 5/6] futex: handle timeout inside adaptive lock ..., Gregory Haskins, (Wed Apr 7, 11:44 am)

Re: [PATCH 4/6] futex: Add FUTEX_LOCK with optional adapti ..., Thomas Gleixner, (Wed Apr 7, 12:59 pm)

Re: [PATCH 5/6] futex: handle timeout inside adaptive lock ..., Darren Hart, (Wed Apr 7, 4:15 pm)

Re: [PATCH 4/6] futex: Add FUTEX_LOCK with optional adapti ..., Darren Hart, (Wed Apr 7, 8:25 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Darren Hart, (Wed Apr 7, 8:33 pm)

Re: [PATCH 6/6] futex: Add aggressive adaptive spinning ar ..., Darren Hart, (Wed Apr 7, 10:58 pm)

Re: [PATCH 4/6] futex: Add FUTEX_LOCK with optional adapti ..., Peter W. Morreale, (Thu Apr 8, 4:10 pm)

Re: [PATCH 4/6] futex: Add FUTEX_LOCK with optional adapti ..., Darren Hart, (Thu Apr 8, 10:41 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., john cooper, (Thu Apr 8, 10:52 pm)

Re: [PATCH 4/6] futex: Add FUTEX_LOCK with optional adapti ..., Peter W. Morreale, (Fri Apr 9, 6:13 am)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Alan Cox, (Sat Apr 10, 4:35 pm)

Re: [PATCH V2 0/6][RFC] futex: FUTEX_LOCK with optional ad ..., Ulrich Drepper