The free OSR Learning Library has more than 50 articles on a wide variety of topics about writing and debugging device drivers and Minifilters. From introductory level to advanced. All the articles have been recently reviewed and updated, and are written using the clear and definitive style you've come to expect from OSR over the years.
Check out The OSR Learning Library at: https://www.osr.com/osr-learning-library/
I see, during PCIe busmastering to system RAM, seemingly random pauses. The Xilinx PCIe block holds back the data flow, I assume in response to the Windows host throttling it. Suspecting contention with unknown processes' memory transfers, I try stressing by running multiple memcpy() in separate processes... and the pauses in my busmastering go DOWN, i.e. performance improves... the maximum pauses are reduced at least by half.
I wildly speculate that the OS sees heavy memory activity and provides me with some memory block that is not in contention with that activity, whereas under normal conditions the OS is aware of contention but doesn't care to optimize at that level.
Could that be? What could explain this? In what direction should I look to reduce these busmaster timeouts?
(I get the statistically same (roughly) timeouts on multiple machines, on the order of 12 microseconds, PCIe 3.0 x8)
|Upcoming OSR Seminars|
|OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!|
|Writing WDF Drivers||7 Dec 2020||LIVE ONLINE|
|Internals & Software Drivers||25 Jan 2021||LIVE ONLINE|
|Developing Minifilters||8 March 2021||LIVE ONLINE|