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
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 contention,
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
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
> 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
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
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
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 megabytes
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
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 2001, Ro
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
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
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
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
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
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
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
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 are
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-not
have
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 loop to
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 definite
advantage to
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 2001, Roger Larsson wrote:
On Thursday 14 June 2001 23:05
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