Hi!
> The 'read()' routine uses a spinlock when it modifies pointers.
>
> I started to look into where all the CPU clocks were going. The
> SMP spinlock code is where it's going. There is often contention
> for the lock because interrupts normally occur at 50 to 60 kHz.
>
> When there is conten
On Fri, 15 Jun 2001, David Schwartz wrote:
>
> > Spinlocks are machine dependent. A simple increment of a byte
> > memory variable, spinning if it's not 1 will do fine. Decrementing
> > this variable will release the lock. A `lock` prefix is not necessary
>
On Fri, 15 Jun 2001, Ingo Oeser wrote:
> On Thu, Jun 14, 2001 at 05:05:07PM -0400, Richard B. Johnson wrote:
> > The problem is that a data acquisition board across the PCI bus
> > gives a data transfer rate of 10 to 11 megabytes per second
> > with a UP kernel, and the transfer drops to 5-6 mega
On Thu, Jun 14, 2001 at 05:05:07PM -0400, Richard B. Johnson wrote:
> The problem is that a data acquisition board across the PCI bus
> gives a data transfer rate of 10 to 11 megabytes per second
> with a UP kernel, and the transfer drops to 5-6 megabytes per
> second with a SMP kernel. The ISR is
> Spinlocks are machine dependent. A simple increment of a byte
> memory variable, spinning if it's not 1 will do fine. Decrementing
> this variable will release the lock. A `lock` prefix is not necessary
> because all Intel
4 Jun 2001, Richard B. Johnson wrote:
> Date: Thu, 14 Jun 2001 23:21:35 -0400 (EDT)
> From: Richard B. Johnson <[EMAIL PROTECTED]>
> To: Roger Larsson <[EMAIL PROTECTED]>
> Cc: Linux kernel <[EMAIL PROTECTED]>
> Subject: Re: SMP spin-locks
>
> On Thu, 14 Jun 200
On Thu, 14 Jun 2001, Roger Larsson wrote:
> On Thursday 14 June 2001 23:05, you wrote:
> > On Thu, 14 Jun 2001, Roger Larsson wrote:
> > > Hi,
> > >
> > > Wait a minute...
> > >
> > > Spinlocks on a embedded system? Is it _really_ SMP?
> >
> > The embedded system is not SMP. However, there is def
Kurt Garloff wrote:
>
> On Thu, Jun 14, 2001 at 01:26:05PM -0400, Richard B. Johnson wrote:
> > Question 2: What is the purpose of the code sequence, "repz nop"
>
> Puts iP4 into low power mode.
Umm, slightly more accurate would be to say that it makes the P4 processor
wait before resuming the
On Thursday 14 June 2001 23:05, you wrote:
> On Thu, 14 Jun 2001, Roger Larsson wrote:
> > Hi,
> >
> > Wait a minute...
> >
> > Spinlocks on a embedded system? Is it _really_ SMP?
>
> The embedded system is not SMP. However, there is definite
> advantage to using an unmodified kernel that may/may-
On Thu, 14 Jun 2001, Roger Larsson wrote:
> Hi,
>
> Wait a minute...
>
> Spinlocks on a embedded system? Is it _really_ SMP?
>
The embedded system is not SMP. However, there is definite
advantage to using an unmodified kernel that may/may-not
have been compiled for SMP. Of course spin-locks ar
Hi,
Wait a minute...
Spinlocks on a embedded system? Is it _really_ SMP?
What kind of performance problem do you have?
My guess, since you are mentioning spin locks, is that you are
having a latency problem - RT process does not execute/start
quickly enough?
If that is the case you should look
On Thu, Jun 14, 2001 at 01:26:05PM -0400, Richard B. Johnson wrote:
> Question 2: What is the purpose of the code sequence, "repz nop"
Puts iP4 into low power mode.
Regards,
--
Kurt Garloff <[EMAIL PROTECTED]> Eindhoven, NL
GPG key: See mail header, key servers
I __finally__ got back on "the list". They finally fixed the
company firewall!
During my absence, I had the chance to look at some SMP code
because of a performance problem (a few microseconds out of
spec on a 130 MHz embedded system) and I have a question about
the current spin-locks.
Spin-lo
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