DPC is supposed to run through unless itself gives up or ISR steps in. How
about SMP? Could it be another PASSIVE_LEVEL run another CPU while the DPC
is on one CPU?
Thanks
Ta
Check out the latest news, polls and tools in the MSN 2004 Election Guide!
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A DPC only affects the process it’s running on. It will run through
until it yields and can be interrupted by higher-priority events
(interrupts) but the other CPUs are free to run passive-level code.
-p
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ta H.
Sent: Friday, July 09, 2004 9:41 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] DPC and SMP
DPC is supposed to run through unless itself gives up or ISR steps in.
How about SMP? Could it be another PASSIVE_LEVEL run another CPU while
the DPC is on one CPU?
Thanks
Ta
Check out the latest news, polls and tools in the MSN 2004 Election
Guide!
http://special.msn.com/msn/election2004.armx
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
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> DPC is supposed to run through unless itself gives up or ISR
steps in. How
about SMP? Could it be another PASSIVE_LEVEL run another CPU
while the DPC
is on one CPU?
I don’t think another processor can have a different IRQL. I did a
web-search, found lots of references to IRQL and Multiprocessor, but all the
texts I could find seem to indicate that IRQL is global (but didn’t say so
directly).
–
Mats
Thanks
Ta
Check out the latest news, polls and tools in the MSN 2004
Election Guide!
http://special.msn.com/msn/election2004.armx
Questions? First check the Kernel Driver FAQ at
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No. IRQL is per-processor, as Peter Wieland said. To serialize between
processors, you need a lock or something similar (albeit nothing else comes
to mind).
Think of higher IRQLs as something like a mask bit on the CPU, eg,
preventing interrupts from registering. (IRQL is not really that – it is
sometimes more, sometimes less – but that’s an analogy to get one
thinking.)
–
James Antognini
Windows DDK Support
This posting is provided “AS IS” with no warranties, and confers no rights.
wrote in message news:xxxxx@ntdev…
> > DPC is supposed to run through unless itself gives up or ISR
> > steps in. How
> > about SMP? Could it be another PASSIVE_LEVEL run another CPU
> > while the DPC
> > is on one CPU?
>
> I don’t think another processor can have a different IRQL. I did a
> web-search, found lots of references to IRQL and Multiprocessor, but all
the
> texts I could find seem to indicate that IRQL is global (but didn’t say so
> directly).
>
> –
> Mats
> >
> > Thanks
> >
> > Ta
> >
> > _________________________________________________________________
> > Check out the latest news, polls and tools in the MSN 2004
> > Election Guide!
> > http://special.msn.com/msn/election2004.armx
> >
> >
> > —
> > Questions? First check the Kernel Driver FAQ at
> > http://www.osronline.com/article.cfm?id=256
> >
> > You are currently subscribed to ntdev as: xxxxx@3dlabs.com
> > To unsubscribe send a blank email to xxxxx@lists.osr.com
> >
>
Yes.
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com
----- Original Message -----
From: “Ta H.”
To: “Windows System Software Devs Interest List”
Sent: Friday, July 09, 2004 8:40 PM
Subject: [ntdev] DPC and SMP
> DPC is supposed to run through unless itself gives up or ISR steps in. How
> about SMP? Could it be another PASSIVE_LEVEL run another CPU while the DPC
> is on one CPU?
>
> Thanks
>
> Ta
>
> _________________________________________________________________
> Check out the latest news, polls and tools in the MSN 2004 Election Guide!
> http://special.msn.com/msn/election2004.armx
>
>
> —
> Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
> web-search, found lots of references to IRQL and Multiprocessor, but all the
texts I could find seem to indicate that IRQL is global (but didn’t say so
IRQL is per-CPU.
The values of PASSIVE and APC_LEVEL are also per-thread - if the thread running
on APC_LEVEL will be preempted, then the control will return to it on APC_LEVEL
again
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com
Why bother to post speculation? Why not wait until somebody who knows the
answer posts it?
(By the way, IRQL is definitely per-processor. It’s completely possible for
a processor running a PASSIVE_LEVEL thread to run while a DPC is running.)
–
Jake Oshins
Windows Kernel Group
This posting is provided “AS IS” with no warranties, and confers no rights.
wrote in message news:xxxxx@ntdev…
>> DPC is supposed to run through unless itself gives up or ISR
>> steps in. How
>> about SMP? Could it be another PASSIVE_LEVEL run another CPU
>> while the DPC
>> is on one CPU?
>
> I don’t think another processor can have a different IRQL. I did a
> web-search, found lots of references to IRQL and Multiprocessor, but all
> the
> texts I could find seem to indicate that IRQL is global (but didn’t say so
> directly).
>
> –
> Mats
>>
>> Thanks
>>
>> Ta
>>
>> _________________________________________________________________
>> Check out the latest news, polls and tools in the MSN 2004
>> Election Guide!
>> http://special.msn.com/msn/election2004.armx
>>
>>
>> —
>> Questions? First check the Kernel Driver FAQ at
>> http://www.osronline.com/article.cfm?id=256
>>
>> You are currently subscribed to ntdev as: xxxxx@3dlabs.com
>> To unsubscribe send a blank email to xxxxx@lists.osr.com
>>
>