Fw: Re: Cached and non cached common buffer

----- Original Message -----
From: Klaus Gerlicher
To: ‘hesham’
Sent: Monday, July 23, 2001 10:00 AM
Subject: RE: [ntdev] Re: Cached and non cached common buffer

Wat OS are you using? W2K, XP or NT4.0?

I have not experimented with HalAllocateCommonBuffer() (which I assume you’re using), but setting the cache flag to TRUE should give you cached physically contiguous memory and thus reach the assumed performance.

Klaus P.

-----Original Message-----
From: hesham [mailto:xxxxx@yahoo.com]
Sent: Montag, 23. Juli 2001 18:01
To: Klaus Gerlicher
Subject: Re: [ntdev] Re: Cached and non cached common buffer

Thanks for these informations, they really make me many things up.
ok I will give you infos about what I have now:
I tried to change the Caching flag in the AllocateCommonBuffer call. After
that I tried to copy memory from the common buffer to another place in
system memory. This memory copying done in the user space into user mode
buffer. Surprise is I have no difference : 20 Frames per second (with each
Frame = 1 MB).
After that Itried thing else. I have allocated a simillar buffer in the
driver using ExAllocatePool().
Copying from this buffer give a performance of 200 Frames per second.
I don’t know what is the Common buffer memory and the NonPagedPool.

so can you find any thing here that I miss

thanks in advance


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