Re: Re: [ntdev] User kernel communication via existing kernel objects

Using reverse IOCTL I was getting about 3.5 meg throughput. Using shared
memory I am getting around 14 meg. That is on my test rig; nothing special.
Performance was improved. The job of the UM coders was made easier too.

With reverse IOCTL, I had to send an IOCTL per request. If I process a
million of those, there is overhead. With shared memory (section objects),
the memory is mapped up front and stays mapped until the UM process
disconnect or exits.

On Wed, Jan 14, 2015 at 6:18 PM, Marion Bond wrote:

> Did you compare the performance against a simple IOCTL implementation?
> Chances are that if you have no race conditions or other logic errors, you
> have rewritten the same thing
>
> Sent from Surface Pro
>
> From: Jamey Kirby
> Sent: ‎Wednesday‎, ‎January‎ ‎14‎, ‎2015 ‎4‎:‎49‎ ‎PM
> To: Windows System Software Devs Interest List
>
> I just finished a driver where I share events and a section object between
> user-mode and kernel-mode. It works great. Performance is high. IOCTLs are
> OK for simple things, but reverse-callbacks are a pain in the arse; not to
> mention that they make me nervous.
>
> On Wed, Jan 14, 2015 at 3:07 PM, Doğan Kurt
> wrote:
>
>> Hello everyone,
>>
>> I like communicating via communication port in minifilter drivers. But i
>> don’t want to register a minifilter driver to use this kind of
>> communication every time.
>>
>> Can i use existing kernel objects, like files, pipes, sockets to
>> communicate with my driver. Which way would you choose if you had to create
>> a generic protocol between kernel and user, without ioctls or irp major
>> functions.
>>
>> Please forgive my ignorance, if i asked something stupid :).
>> Thanks in advance.
>> — NTDEV is sponsored by OSR Visit the list at:
>> http://www.osronline.com/showlists.cfm?list=ntdev OSR is HIRING!! See
>> http://www.osr.com/careers For our schedule of WDF, WDM, debugging and
>> other seminars visit: http://www.osr.com/seminars To unsubscribe, visit
>> the List Server section of OSR Online at
>> http://www.osronline.com/page.cfm?name=ListServer
>
>
>
>
> –
> Jamey Kirby
> Disrupting the establishment since 1964
>
> This is a personal email account and as such, emails are not subject to
> archiving. Nothing else really matters.

> — NTDEV is sponsored by OSR Visit the list at:
> http://www.osronline.com/showlists.cfm?list=ntdev OSR is HIRING!! See
> http://www.osr.com/careers For our schedule of WDF, WDM, debugging and
> other seminars visit: http://www.osr.com/seminars To unsubscribe, visit
> the List Server section of OSR Online at
> http://www.osronline.com/page.cfm?name=ListServer
>
> —
> NTDEV is sponsored by OSR
>
> Visit the list at: http://www.osronline.com/showlists.cfm?list=ntdev
>
> OSR is HIRING!! See http://www.osr.com/careers
>
> For our schedule of WDF, WDM, debugging and other seminars visit:
> http://www.osr.com/seminars
>
> To unsubscribe, visit the List Server section of OSR Online at
> http://www.osronline.com/page.cfm?name=ListServer
>


Jamey Kirby
Disrupting the establishment since 1964

This is a personal email account and as such, emails are not subject to
archiving. Nothing else really matters.