Re: incorrect usleep/select delays with HZ > 2500

2009-09-21 Thread Matthew Dillon
What we wound up doing was splitting tvtohz() into two functions. tvtohz_high(tv) Returned value meets or exceeds requested time. A minimum value of 1 is returned (really only for {0,0}.. else minimum value is 2). tvtohz_low(tv) Returned value might be short

Re: incorrect usleep/select delays with HZ > 2500

2009-09-10 Thread Luigi Rizzo
On Thu, Sep 10, 2009 at 11:02:19PM +0930, Daniel O'Connor wrote: > On Thu, 10 Sep 2009, John Baldwin wrote: > > > $ARCH/isa/clock.c::DELAY(). I suppose with a few measurements > > > at different HZ values and some back of the envelope calculations > > > one could even determine estimate the frequen

Re: incorrect usleep/select delays with HZ > 2500

2009-09-10 Thread Daniel O'Connor
On Thu, 10 Sep 2009, John Baldwin wrote: > > $ARCH/isa/clock.c::DELAY(). I suppose with a few measurements > > at different HZ values and some back of the envelope calculations > > one could even determine estimate the frequency and duration > > of those SMI interrupts! > > On recent motherboards I

Re: incorrect usleep/select delays with HZ > 2500

2009-09-09 Thread Luigi Rizzo
On Wed, Sep 09, 2009 at 04:42:05PM -0400, John Baldwin wrote: ... > > > It would explain why it gets better later since the uhci(4), ohci(4) and > > > ehci(4) drivers disable the SMI# interrupts while attaching to the > > > controllers. > > > > ok makes sense -- if the SMI interrupts last longer

Re: incorrect usleep/select delays with HZ > 2500

2009-09-09 Thread John Baldwin
On Wednesday 09 September 2009 4:32:16 pm Luigi Rizzo wrote: > On Wed, Sep 09, 2009 at 01:24:53PM -0400, John Baldwin wrote: > > On Tuesday 08 September 2009 5:01:00 pm Luigi Rizzo wrote: > > > On Tue, Sep 08, 2009 at 01:08:23PM -0400, John Baldwin wrote: > > > > On Sunday 06 September 2009 11:51:5

Re: incorrect usleep/select delays with HZ > 2500

2009-09-09 Thread Luigi Rizzo
On Wed, Sep 09, 2009 at 01:24:53PM -0400, John Baldwin wrote: > On Tuesday 08 September 2009 5:01:00 pm Luigi Rizzo wrote: > > On Tue, Sep 08, 2009 at 01:08:23PM -0400, John Baldwin wrote: > > > On Sunday 06 September 2009 11:51:54 am Luigi Rizzo wrote: > > > > [Note 3] the TSC frequency is compute

Re: incorrect usleep/select delays with HZ > 2500

2009-09-09 Thread John Baldwin
On Tuesday 08 September 2009 5:01:00 pm Luigi Rizzo wrote: > On Tue, Sep 08, 2009 at 01:08:23PM -0400, John Baldwin wrote: > > On Sunday 06 September 2009 11:51:54 am Luigi Rizzo wrote: > > > [Note 3] the TSC frequency is computed reading the tsc around a > > > call to DELAY(100) and as

Re: incorrect usleep/select delays with HZ > 2500

2009-09-08 Thread Luigi Rizzo
On Tue, Sep 08, 2009 at 01:08:23PM -0400, John Baldwin wrote: > On Sunday 06 September 2009 11:51:54 am Luigi Rizzo wrote: > > [Note 3] the TSC frequency is computed reading the tsc around a > > call to DELAY(100) and assuming that the i8254 runs > > at the nominal rate, 1.19318

Re: incorrect usleep/select delays with HZ > 2500

2009-09-08 Thread John Baldwin
On Sunday 06 September 2009 11:51:54 am Luigi Rizzo wrote: > [Note 3] the TSC frequency is computed reading the tsc around a > call to DELAY(100) and assuming that the i8254 runs > at the nominal rate, 1.193182 MHz. > From tests I have made, the measurement in init_TSC()

Re: incorrect usleep/select delays with HZ > 2500

2009-09-07 Thread Chuck Swiger
Hi, all-- On Sep 7, 2009, at 12:21 AM, Luigi Rizzo wrote: 3. ?CAUSE an error in tvtohz(), reported long ago in ? ? ? ?http://www.dragonflybsd.org/presentations/nanosleep/ ? ? ? ?which causes a systematic error of an extra tick in the computation ? ? ? ?of the sleep times. ? ?FIX: the above li

Re: incorrect usleep/select delays with HZ > 2500

2009-09-07 Thread Clifton Royston
On Mon, Sep 07, 2009 at 09:21:59AM +0200, Luigi Rizzo wrote: > On Sun, Sep 06, 2009 at 05:36:29PM -0700, Peter Wemm wrote: > > On Sun, Sep 6, 2009 at 8:51 AM, Luigi Rizzo wrote: > > > (this problem seems to affect both current and -stable, > > > so let's see if here i have better luck) > > > > > >

Re: incorrect usleep/select delays with HZ > 2500

2009-09-07 Thread Luigi Rizzo
On Sun, Sep 06, 2009 at 05:36:29PM -0700, Peter Wemm wrote: > On Sun, Sep 6, 2009 at 8:51 AM, Luigi Rizzo wrote: > > (this problem seems to affect both current and -stable, > > so let's see if here i have better luck) > > > > I just noticed [Note 1,2] that when setting HZ > 2500 (even if it is > >

Re: incorrect usleep/select delays with HZ > 2500

2009-09-06 Thread Peter Wemm
On Sun, Sep 6, 2009 at 8:51 AM, Luigi Rizzo wrote: > (this problem seems to affect both current and -stable, > so let's see if here i have better luck) > > I just noticed [Note 1,2] that when setting HZ > 2500 (even if it is > an exact divisor of the APIC/CPU clock) there is a significant > drift b