Re: APIC priorities, can they be changed?

[Florian Schmidt]

On Thursday 15 February 2007, Mike Panetta wrote:
> I did try that.  The BIOS only allows me to either allocate an IRQ to be
> a PCI interrupt, or reserve it (for what I have no idea).  The IRQ's
> listed in the BIOS are also different from the ones Linux sees.  I think
> the BIOS is seeing the XT-PIC IRQ numbers and Linux is seeing the APIC
> numbers.  For example the little bios blurb that prints before the
> system boots says the USB controller I am interested in is
> assigned/using IRQ 10, Linux sees it using IRQ 18.
>
> I have found that I can keep Linux from using the APIC by disabling it
> with a kernel command line switch, but that does not help, it just makes
> Linux use the XT-PIC instead of the IO-APIC to do IRQ routing.
>
> So I guess I'm back to my original question of  'Would changing the
> vector numbers do what I want?' and if the answer is 'yes', how would I
> do it?

With XT-PIC, there was a way to change the priotrities used by the IRQ. It was 
called irqtune iirc.

Ah ya,

http://cae.best.vwh.net/irqtune/

Dunno if there's something similar available for APIC..

Regards,
Flo

-- 
Palimm Palimm!
http://tapas.affenbande.org
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Re: APIC priorities, can they be changed?

[Florian Schmidt]

On Thursday 15 February 2007, Mike Panetta wrote:
 I did try that.  The BIOS only allows me to either allocate an IRQ to be
 a PCI interrupt, or reserve it (for what I have no idea).  The IRQ's
 listed in the BIOS are also different from the ones Linux sees.  I think
 the BIOS is seeing the XT-PIC IRQ numbers and Linux is seeing the APIC
 numbers.  For example the little bios blurb that prints before the
 system boots says the USB controller I am interested in is
 assigned/using IRQ 10, Linux sees it using IRQ 18.

 I have found that I can keep Linux from using the APIC by disabling it
 with a kernel command line switch, but that does not help, it just makes
 Linux use the XT-PIC instead of the IO-APIC to do IRQ routing.

 So I guess I'm back to my original question of  'Would changing the
 vector numbers do what I want?' and if the answer is 'yes', how would I
 do it?

With XT-PIC, there was a way to change the priotrities used by the IRQ. It was 
called irqtune iirc.

Ah ya,

http://cae.best.vwh.net/irqtune/

Dunno if there's something similar available for APIC..

Regards,
Flo

-- 
Palimm Palimm!
http://tapas.affenbande.org
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
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Re: APIC priorities, can they be changed?

[Mike Panetta]

linux-os (Dick Johnson) wrote:


On Thu, 15 Feb 2007, Mike Panetta wrote:

> I am not on the list (corperate email sucks) so please CC any replies to
> me.  Thanks.

[snip]

> I have seen the preempt patches, but they touch a lot of files, and we
> have gone through testing with the 2.6.16.19 kernel and do not wish to
> change, and we cannot find a version of the patch for this kernel. Is
> there something smaller/simpler I can do?  My understanding is the
> priority in the APIC is set in software via the interrupt vector number
> (higher numbers have lower priority) is this true?  If so, how hard
> would it be for me to just change the vector numbers around?
>

[snip]

> Thanks,
> Mike

Can't you muck with the BIOS settings? That's where the primary
hardware gets 'connected'.



I did try that.  The BIOS only allows me to either allocate an IRQ to be 
a PCI interrupt, or reserve it (for what I have no idea).  The IRQ's 
listed in the BIOS are also different from the ones Linux sees.  I think 
the BIOS is seeing the XT-PIC IRQ numbers and Linux is seeing the APIC 
numbers.  For example the little bios blurb that prints before the 
system boots says the USB controller I am interested in is 
assigned/using IRQ 10, Linux sees it using IRQ 18.


I have found that I can keep Linux from using the APIC by disabling it 
with a kernel command line switch, but that does not help, it just makes 
Linux use the XT-PIC instead of the IO-APIC to do IRQ routing.


So I guess I'm back to my original question of  'Would changing the 
vector numbers do what I want?' and if the answer is 'yes', how would I 
do it?


Thanks,
Mike



Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.61 BogoMips).
New book: http://www.AbominableFirebug.com/
_



The information transmitted in this message is confidential and may be 
privileged.  Any review, retransmission, dissemination, or other use 
of this information by persons or entities other than the intended 
recipient is prohibited.  If you are not the intended recipient, 
please notify Analogic Corporation immediately - by replying to this 
message or by sending an email to [EMAIL PROTECTED] 
 - and destroy all copies of this 
information, including any attachments, without reading or disclosing 
them.


Thank you.



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Re: APIC priorities, can they be changed?

[linux-os \(Dick Johnson\)]

On Thu, 15 Feb 2007, Mike Panetta wrote:

> I am not on the list (corperate email sucks) so please CC any replies to
> me.  Thanks.
>
> I am working on a project that has run in to what seems to be an
> interrupt priority problem.  We switched mainboards in our product and
> went from a system where the EHCI controller IRQ was of a fairly high
> priority to one where its the lowest in the system.  Now we cannot get
> the data off our USB device in time and we drop alot of data.  I was
> hoping someone here may have a simple(ish) solution to the problem.
>
> I have seen the preempt patches, but they touch a lot of files, and we
> have gone through testing with the 2.6.16.19 kernel and do not wish to
> change, and we cannot find a version of the patch for this kernel. Is
> there something smaller/simpler I can do?  My understanding is the
> priority in the APIC is set in software via the interrupt vector number
> (higher numbers have lower priority) is this true?  If so, how hard
> would it be for me to just change the vector numbers around?
>
> Ideally I would love to switch to the 2.6.20 kernel and use the preempt
> patch, but I doubt we have the time for that.
>
> Thanks,
> Mike

Can't you muck with the BIOS settings? That's where the primary
hardware gets 'connected'.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.61 BogoMips).
New book: http://www.AbominableFirebug.com/
_



The information transmitted in this message is confidential and may be 
privileged.  Any review, retransmission, dissemination, or other use of this 
information by persons or entities other than the intended recipient is 
prohibited.  If you are not the intended recipient, please notify Analogic 
Corporation immediately - by replying to this message or by sending an email to 
[EMAIL PROTECTED] - and destroy all copies of this information, including any 
attachments, without reading or disclosing them.

Thank you.
-
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Re: APIC priorities, can they be changed?

[linux-os \(Dick Johnson\)]

On Thu, 15 Feb 2007, Mike Panetta wrote:

 I am not on the list (corperate email sucks) so please CC any replies to
 me.  Thanks.

 I am working on a project that has run in to what seems to be an
 interrupt priority problem.  We switched mainboards in our product and
 went from a system where the EHCI controller IRQ was of a fairly high
 priority to one where its the lowest in the system.  Now we cannot get
 the data off our USB device in time and we drop alot of data.  I was
 hoping someone here may have a simple(ish) solution to the problem.

 I have seen the preempt patches, but they touch a lot of files, and we
 have gone through testing with the 2.6.16.19 kernel and do not wish to
 change, and we cannot find a version of the patch for this kernel. Is
 there something smaller/simpler I can do?  My understanding is the
 priority in the APIC is set in software via the interrupt vector number
 (higher numbers have lower priority) is this true?  If so, how hard
 would it be for me to just change the vector numbers around?

 Ideally I would love to switch to the 2.6.20 kernel and use the preempt
 patch, but I doubt we have the time for that.

 Thanks,
 Mike

Can't you muck with the BIOS settings? That's where the primary
hardware gets 'connected'.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.61 BogoMips).
New book: http://www.AbominableFirebug.com/
_



The information transmitted in this message is confidential and may be 
privileged.  Any review, retransmission, dissemination, or other use of this 
information by persons or entities other than the intended recipient is 
prohibited.  If you are not the intended recipient, please notify Analogic 
Corporation immediately - by replying to this message or by sending an email to 
[EMAIL PROTECTED] - and destroy all copies of this information, including any 
attachments, without reading or disclosing them.

Thank you.
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
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Please read the FAQ at  http://www.tux.org/lkml/

Re: APIC priorities, can they be changed?

[Mike Panetta]

linux-os (Dick Johnson) wrote:


On Thu, 15 Feb 2007, Mike Panetta wrote:

 I am not on the list (corperate email sucks) so please CC any replies to
 me.  Thanks.

[snip]

 I have seen the preempt patches, but they touch a lot of files, and we
 have gone through testing with the 2.6.16.19 kernel and do not wish to
 change, and we cannot find a version of the patch for this kernel. Is
 there something smaller/simpler I can do?  My understanding is the
 priority in the APIC is set in software via the interrupt vector number
 (higher numbers have lower priority) is this true?  If so, how hard
 would it be for me to just change the vector numbers around?


[snip]

 Thanks,
 Mike

Can't you muck with the BIOS settings? That's where the primary
hardware gets 'connected'.



I did try that.  The BIOS only allows me to either allocate an IRQ to be 
a PCI interrupt, or reserve it (for what I have no idea).  The IRQ's 
listed in the BIOS are also different from the ones Linux sees.  I think 
the BIOS is seeing the XT-PIC IRQ numbers and Linux is seeing the APIC 
numbers.  For example the little bios blurb that prints before the 
system boots says the USB controller I am interested in is 
assigned/using IRQ 10, Linux sees it using IRQ 18.


I have found that I can keep Linux from using the APIC by disabling it 
with a kernel command line switch, but that does not help, it just makes 
Linux use the XT-PIC instead of the IO-APIC to do IRQ routing.


So I guess I'm back to my original question of  'Would changing the 
vector numbers do what I want?' and if the answer is 'yes', how would I 
do it?


Thanks,
Mike



Cheers,
Dick Johnson
Penguin : Linux version 2.6.16.24 on an i686 machine (5592.61 BogoMips).
New book: http://www.AbominableFirebug.com/
_



The information transmitted in this message is confidential and may be 
privileged.  Any review, retransmission, dissemination, or other use 
of this information by persons or entities other than the intended 
recipient is prohibited.  If you are not the intended recipient, 
please notify Analogic Corporation immediately - by replying to this 
message or by sending an email to [EMAIL PROTECTED] 
mailto:[EMAIL PROTECTED] - and destroy all copies of this 
information, including any attachments, without reading or disclosing 
them.


Thank you.



-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
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