Doron is probably referring to this whitepaper
http://www.microsoft.com/whdc/system/Sysinternals/MoreThan64proc.mspx
It has these tantalizing headings in its table of contents:
Kernel-Mode Driver Modifications
Per-Processor Data Structures
Static Array
Dynamic Array
-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of Doron Holan
Sent: Thursday, August 27, 2009 7:01 PM
To: Windows System Software Devs Interest List
Subject: RE: Re:[ntdev] Driver contract changes in Win 7
There is a document on whdc, i do not have access to a pc to check for the exact link. There are notifications about processor changes that you can subscribe to that you can use to dynamically reallocate structures to account for the change in the number of procs
d
Sent from my phone with no t9, all spilling mistakes are not intentional.
-----Original Message-----
From: James Harper
Sent: Thursday, August 27, 2009 6:13 PM
To: Windows System Software Devs Interest List
Subject: RE: Re:[ntdev] Driver contract changes in Win 7
>
> Another contract change that was introduced in server 2008 R2 was
greater than
> 64 proc support. This has 2 visible changes
> 1) MAXIMUM_PROCESSORS is now meaningless
> 2) If a driver was using the current processor’s index in the affinity
mask as
> an index into their own data structure (such as an array bounded which
has
> MAXIMUM_PROCESSORS elements), while the index will never exceed
> MAXIMUM_PROCESSORS so you will not go off the end of the array, 2
concurrent
> threads of execution (be it dispatch routines, DPCs, whatever) can
both have
> the same index but be in different processor groups, thus invalidating
the
> assumption that the index can be used lock free or exclusively or as
some type
> of unique id
>
Is there a document that describes how a driver should maintain per-cpu data under this new regime? Or is doing that a no-no from windows 7 onwards?
Thanks
James
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