Well, VA is a limit on x86. On a 64 bit machine, you have a ton more VA
to play with as well.
d
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Tim Roberts
Sent: Tuesday, August 29, 2006 9:06 AM
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] What are reasonable stack limits for our drivers on
WinXP and Vista
Pavel A. wrote:
“Tim Roberts” wrote in message news:xxxxx@ntdev…
>
>
>>>Given the previously discussed reasons why kernel stacks are small,
>>>these 64-bit systems should be real RAM hogs - they must have
>>>lot of committed physical RAM for all these stacks, not just virtual
space ?
>>>
>>>
>>Apparently, about twice as much. But, remember that you’re talking
>>about K bytes here. It is an insignificant amount of memory. My
>>machine has about 500 active threads. So, we’re talking about the
>>difference between 6MB and 12MB.
>>
>>Now, your statement that “these 64-bit systems should be real RAM
hogs”
>>is quite correct, but kernel stacks aren’t the reason…
>>
>>
>
>Then, if we’re takling about only 6 MB - ok let it be 20 MB - of a 1 GB
kernel
>space - why not to double kernel stacks on x86?
>
>
Inertia, probably. Kernel stacks NEED to double on 64-bit architectures
because each stack push is twice as wide. 10 pointers in x64 take twice
the space of 10 pointers in x86.
But overall, there just doesn’t seem to be an overwhelming demand.
There has to be SOME limit, and those of us who write drivers have
learned to fit within the existing (small) limit.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
—
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