Hi All,
I am writing a NDIS-WDM driver for a USB network device.
Is it OK to use NdisInitializeNPagedLookasideList to allocate tx and rx 512 bytes buffer which I send to USB endpoints in the fast path functionality.
Will it hit tx/rx performace too much?
Thanks
Anand
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Yes, you should use it. A lookaside list will be as fast or faster then
calling a pool allocation function (like ExAllocatePool or an NDIS
allocator) since it will be a simple lookup for an allocation if the
list is not empty.
d
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@juno.com
Sent: Sunday, May 01, 2005 9:15 PM
To: Windows System Software Devs Interest List
Subject: [ntdev] NdisInitializeNPagedLookasideList
Hi All,
I am writing a NDIS-WDM driver for a USB network device.
Is it OK to use NdisInitializeNPagedLookasideList to allocate tx and rx
512 bytes buffer which I send to USB endpoints in the fast path
functionality.
Will it hit tx/rx performace too much?
Thanks
Anand
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Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
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Why not? Seems to be a good idea.
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com
----- Original Message -----
From:
To: “Windows System Software Devs Interest List”
Sent: Monday, May 02, 2005 8:15 AM
Subject: [ntdev] NdisInitializeNPagedLookasideList
>
> Hi All,
>
> I am writing a NDIS-WDM driver for a USB network device.
>
> Is it OK to use NdisInitializeNPagedLookasideList to allocate tx and rx 512
bytes buffer which I send to USB endpoints in the fast path functionality.
>
> Will it hit tx/rx performace too much?
>
> Thanks
> Anand
>
> ___________________________________________________________________
> Speed up your surfing with Juno SpeedBand.
> Now includes pop-up blocker!
> Only $14.95/month -visit http://www.juno.com/surf to sign up today!
>
>
> —
> 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
Anand,
The only possible performance effect would be a performance improvement!
The Ndis…NPagedLookasideList is an optimized mechanism for managing fixed
size memory allocations that are frequently allocated & deallocated.
Typically such a pattern can cause heap fragmentation. Using the lookaside
list reduces the heap fragmentation potential by caching a certain number of
allocations in a list and reusing them in favor of asking the Non-Paged pool
for more memory. If the cache (the ‘list’) is empty, NDIS will still go
grab memory from the N-Paged pool to satisfy the request.
Be very sure to free the list when you driver unloads (or before the owning
datastructure is released). NDIS (ok, the kernel) periodically sweeps
through lookaside lists to trim them in an attempt to release NPaged pool
back to the system. Leaving a ‘dangling’ lookaside list is sadly a not too
uncommon bug and will often result in a bugcheck.
Good Luck,
Dave Cattley
Consulting Engineer
Systems Software Development
wrote in message news:xxxxx@ntdev…
>
> Hi All,
>
> I am writing a NDIS-WDM driver for a USB network device.
>
> Is it OK to use NdisInitializeNPagedLookasideList to allocate tx and rx
> 512 bytes buffer which I send to USB endpoints in the fast path
> functionality.
>
> Will it hit tx/rx performace too much?
>
> Thanks
> Anand
>
> ___________________________________________________________________
> Speed up your surfing with Juno SpeedBand.
> Now includes pop-up blocker!
> Only $14.95/month -visit http://www.juno.com/surf to sign up today!
>
>