Maximum number of allocated Spin locks

[Peter_Viscarola_OSR]

I’m puzzled how queueing another DPC fully resolves the DPC watchdog timeout.
There are TWO watchdog timers, one limit for an individual DPC, and another for
back-to-back DPCs. To avoid this second DPC watchdog bugcheck you must give up
the CPU to passive_level for a few moments.

Hmmmm… I guess I wasn’t aware of that, and haven’t encountered it. Maybe I’m just lucky?

Peter
OSR
@OSRDrivers

[Mark_Roddy]

If you are using a high importance dpc object for your requeue, that would
be the wrong thing to do. If you aren’t and you really are running into
this problem, then you could set the cpu for the other dpc to be ‘not this
cpu’.

Mark Roddy

On Tue, Apr 17, 2018 at 10:41 AM, xxxxx@osr.com
wrote:

>

> I’m puzzled how queueing another DPC fully resolves the DPC watchdog
> timeout.
> There are TWO watchdog timers, one limit for an individual DPC, and
> another for
> back-to-back DPCs. To avoid this second DPC watchdog bugcheck you must
> give up
> the CPU to passive_level for a few moments.
>

>
> Hmmmm… I guess I wasn’t aware of that, and haven’t encountered it.
> Maybe I’m just lucky?
>
> Peter
> OSR
> @OSRDrivers
>
>
> —
> NTDEV is sponsored by OSR
>
> Visit the list online at: http:> showlists.cfm?list=ntdev>
>
> MONTHLY seminars on crash dump analysis, WDF, Windows internals and
> software drivers!
> Details at http:
>
> To unsubscribe, visit the List Server section of OSR Online at <
> http://www.osronline.com/page.cfm?name=ListServer&gt;
></http:></http:>

[Jan_Bottorff]

The article at https://blogs.msdn.microsoft.com/ntdebugging/2012/12/07/determining-the-source-of-bug-check-0x133-dpc_watchdog_violation-errors-on-windows-server-2012/ talks about both timeouts.

The API KeQueryDpcWatchdogInformation returns the current and limit values for both timers.

Jan

-----Original Message-----
From: xxxxx@lists.osr.com On Behalf Of xxxxx@osr.com
Sent: Tuesday, April 17, 2018 7:42 AM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] Maximum number of allocated Spin locks

I’m puzzled how queueing another DPC fully resolves the DPC watchdog timeout.
There are TWO watchdog timers, one limit for an individual DPC, and another for back-to-back DPCs. To avoid this second DPC watchdog bugcheck you must give up the CPU to passive_level for a few moments.

Hmmmm… I guess I wasn’t aware of that, and haven’t encountered it. Maybe I’m just lucky?

Peter
OSR
@OSRDrivers

—
NTDEV is sponsored by OSR

Visit the list online at: http:

MONTHLY seminars on crash dump analysis, WDF, Windows internals and software drivers!
Details at http:

To unsubscribe, visit the List Server section of OSR Online at http:</http:></http:></http:>