Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Joe Korty
On Thu, Sep 01, 2005 at 04:32:49PM +0200, Roman Zippel wrote: > On Thu, 1 Sep 2005, Joe Korty wrote: > > Kernel time sucks. It is just a single clock, it may not have > > the attributes of the clock that the user really wished to use. > > Wrong. The kernel time is simple and effective for almost

Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Roman Zippel
Hi, On Thu, 1 Sep 2005, Joe Korty wrote: > On Thu, Sep 01, 2005 at 11:19:51AM +0200, Roman Zippel wrote: > > > You still didn't explain what's the point in choosing > > different clock sources for a _timeout_. > > Well, if CLOCK_REALTIME is set forward by a minute, > timers & timeout specified

Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Daniel Walker
On Thu, 2005-09-01 at 16:32 +0200, Roman Zippel wrote: > Hi, > > On Thu, 1 Sep 2005, Joe Korty wrote: > > > > When you convert a user time to kernel time you can > > > automatically validate > > > > Kernel time sucks. It is just a single clock, it may not have > > the attributes of the clock th

Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Daniel Walker
On Thu, 2005-09-01 at 16:32 +0200, Roman Zippel wrote: > Hi, > > On Thu, 1 Sep 2005, Joe Korty wrote: > > > > When you convert a user time to kernel time you can > > > automatically validate > > > > Kernel time sucks. It is just a single clock, it may not have > > the attributes of the clock th

Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Roman Zippel
Hi, On Thu, 1 Sep 2005, Joe Korty wrote: > > When you convert a user time to kernel time you can > > automatically validate > > Kernel time sucks. It is just a single clock, it may not have > the attributes of the clock that the user really wished to use. Wrong. The kernel time is simple and e

Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Joe Korty
On Thu, Sep 01, 2005 at 01:50:33AM +0200, Roman Zippel wrote: > When you convert a user time to kernel time you can > automatically validate Kernel time sucks. It is just a single clock, it may not have the attributes of the clock that the user really wished to use. Joe - To unsubscribe from thi

Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Joe Korty
On Thu, Sep 01, 2005 at 11:22:32AM +0200, Roman Zippel wrote: > For a timeout? Please get real. > If you need more precision, use a dedicated timer API, but don't make the > general case more complex for the 99.99% of other users. Struct timeout is just a struct timespec + a bit for absolute/rela

Re: FW: [RFC] A more general timeout specification

2005-09-01 Thread Joe Korty
On Thu, Sep 01, 2005 at 11:19:51AM +0200, Roman Zippel wrote: > You still didn't explain what's the point in choosing > different clock sources for a _timeout_. Well, if CLOCK_REALTIME is set forward by a minute, timers & timeout specified against that clock will expire a minute earlier than expe

RE: FW: [RFC] A more general timeout specification

2005-09-01 Thread Roman Zippel
Hi, On Thu, 1 Sep 2005, Perez-Gonzalez, Inaky wrote: > >You still didn't explain what's the point in choosing different clock > >sources for a _timeout_. > > The same reasons that compel to have CLOCK_REALTIME or > CLOCK_MONOTONIC, for example. Or the need to time out on a > high resolution clo

RE: FW: [RFC] A more general timeout specification

2005-09-01 Thread Perez-Gonzalez, Inaky
>From: Roman Zippel [mailto:[EMAIL PROTECTED] >On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > >> Hmm, I cannot think of more ways to specify a timeout than how >> long I want to wait (relative) or until when (absolute) and which >> is the reference clock. And they don't seem broken to me, comm

RE: FW: [RFC] A more general timeout specification

2005-09-01 Thread Roman Zippel
Hi, On Wed, 31 Aug 2005, Daniel Walker wrote: > > What "more versions" are you talking about? When you convert a user time > > to kernel time you can automatically validate it and later you can use > > standard kernel APIs, so you don't have to add even more API bloat. > > What's kernel time?

RE: FW: [RFC] A more general timeout specification

2005-09-01 Thread Roman Zippel
Hi, On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > Hmm, I cannot think of more ways to specify a timeout than how > long I want to wait (relative) or until when (absolute) and which > is the reference clock. And they don't seem broken to me, common > sense, in any case. Do you have any examp

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Daniel Walker
On Thu, 2005-09-01 at 01:50 +0200, Roman Zippel wrote: > What "more versions" are you talking about? When you convert a user time > to kernel time you can automatically validate it and later you can use > standard kernel APIs, so you don't have to add even more API bloat. What's kernel time? Ar

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Perez-Gonzalez, Inaky
>From: Roman Zippel [mailto:[EMAIL PROTECTED] >On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > >> I cannot produce (top of my head) any other POSIX API calls that >> allow you to specify another clock source, but they are there, >> somewhere. If I am to introduce a new API, I better make it >>

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Roman Zippel
Hi, On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > I cannot produce (top of my head) any other POSIX API calls that > allow you to specify another clock source, but they are there, > somewhere. If I am to introduce a new API, I better make it > flexible enough so that other subsystems can u

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Perez-Gonzalez, Inaky
>From: Roman Zippel [mailto:[EMAIL PROTECTED] >On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > >> Usefulness: (see the rationale in the patch), but in a nutshell; >> most POSIX timeout specs have to be absolute in CLOCK_REALTIME >> (eg: pthread_mutex_timed_lock()). Current kernel needs the time

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Perez-Gonzalez, Inaky
>From: Christopher Friesen [mailto:[EMAIL PROTECTED] >Perez-Gonzalez, Inaky wrote: > >>>I can get the first sleep. Suppose I oversleep by X nanoseconds. I >>>wake, and get an opaque timeout back. How do I ask for the new wake >>>time to be "endtime + INTERVAL"? >> >> >> endtime.ts += INTERVAL >>

Re: FW: [RFC] A more general timeout specification

2005-08-31 Thread Christopher Friesen
Perez-Gonzalez, Inaky wrote: I can get the first sleep. Suppose I oversleep by X nanoseconds. I wake, and get an opaque timeout back. How do I ask for the new wake time to be "endtime + INTERVAL"? endtime.ts += INTERVAL [we all know opaque is relative too] Heh. Okay, then what are the r

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Roman Zippel
Hi, On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > >Why is that needed in a _general_ timeout API? What exactly makes it so > >useful for everyone and not just more complex for everyone? > > Because if a system call gets a timeout specification it needs to > verify its correctness first. In

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Perez-Gonzalez, Inaky
>From: Christopher Friesen [mailto:[EMAIL PROTECTED] >Joe Korty wrote: > >> The returned timeout struct has a bit used to mark the value as absolute. Thus >> the caller treats the returned timeout as a opaque cookie that can be >> reapplied to the next (or more likely, the to-be restarted) timeout

RE: FW: [RFC] A more general timeout specification

2005-08-31 Thread Perez-Gonzalez, Inaky
>From: Roman Zippel [mailto:[EMAIL PROTECTED] >On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > >> +flags = tp->clock_id & TIMEOUT_FLAGS_MASK; >> +clock_id = tp->clock_id & TIMEOUT_CLOCK_MASK; >> + >> +result = -EINVAL; >> +if (flags & ~TIMEOUT_RELATIVE) >> +goto out; >>

Re: FW: [RFC] A more general timeout specification

2005-08-31 Thread Roman Zippel
Hi, On Wed, 31 Aug 2005, Perez-Gonzalez, Inaky wrote: > + flags = tp->clock_id & TIMEOUT_FLAGS_MASK; > + clock_id = tp->clock_id & TIMEOUT_CLOCK_MASK; > + > + result = -EINVAL; > + if (flags & ~TIMEOUT_RELATIVE) > + goto out; > + > + /* someday, we should support *all*

Re: FW: [RFC] A more general timeout specification

2005-08-31 Thread Christopher Friesen
Joe Korty wrote: The returned timeout struct has a bit used to mark the value as absolute. Thus the caller treats the returned timeout as a opaque cookie that can be reapplied to the next (or more likely, the to-be restarted) timeout. Okay, endtime is always absolute value of when it should h

Re: FW: [RFC] A more general timeout specification

2005-08-31 Thread Joe Korty
On Wed, Aug 31, 2005 at 03:20:03PM -0600, Christopher Friesen wrote: > Perez-Gonzalez, Inaky wrote: > >In this structure, > >the user specifies: > >whether the time is absolute, or relative to 'now'. > > > >Timeout_sleep has a return argument, endtime, which is also in > >'struct timeout' for

Re: FW: [RFC] A more general timeout specification

2005-08-31 Thread Christopher Friesen
Perez-Gonzalez, Inaky wrote: In this structure, the user specifies: whether the time is absolute, or relative to 'now'. Timeout_sleep has a return argument, endtime, which is also in 'struct timeout' format. If the input time was relative, then it is converted to absolute and returned th

Re: FW: [RFC] A more general timeout specification

2005-08-31 Thread Joe Korty
On Wed, Aug 31, 2005 at 01:55:54PM -0700, Perez-Gonzalez, Inaky wrote: > Hi Andrew > > This was developed by Joe Korty <[EMAIL PROTECTED]>, greatly > enhancing something I had done before, so I am signing it out > (although Joe should too, Joe?). The fusyn (robust mutexes) project proposes the

FW: [RFC] A more general timeout specification

2005-08-31 Thread Perez-Gonzalez, Inaky
Hi Andrew I would like to ask for the inclusion of the general timeout specification API in the -mm tree, looking forward it to bubble up to mainline. For more context, please visit: http://groups.google.com/group/linux.kernel/browse_frm/thread/a426e5b0d0 f17860/b53000aa01304c4a?tvc=1&q=a+more

RE: FW: [RFC] A more general timeout specification

2005-08-22 Thread Perez-Gonzalez, Inaky
Hi John >From: john stultz [mailto:[EMAIL PROTECTED] >On Thu, 2005-07-28 at 18:52 -0700, Inaky Perez-Gonzalez wrote: >> The main user of this new inteface is to allow system calls to get >> time specified in an absolute form (as most of POSIX states) and thus >> avoid extra time conversion work. .

Re: FW: [RFC] A more general timeout specification

2005-08-22 Thread john stultz
On Thu, 2005-07-28 at 18:52 -0700, Inaky Perez-Gonzalez wrote: > The main user of this new inteface is to allow system calls to get > time specified in an absolute form (as most of POSIX states) and thus > avoid extra time conversion work. > > There was a short thread about it, available at google

FW: [RFC] A more general timeout specification

2005-07-28 Thread Inaky Perez-Gonzalez
Hi John Couple of months ago Joe Korty sent the attached proposal for a new interface and I was wondering if you could comment on it. The main user of this new inteface is to allow system calls to get time specified in an absolute form (as most of POSIX states) and thus avoid extra time conversi