Write-combining

[Thiago Robert]

Hello there!

Is there an easy way to be sure about wether the PCI write-combining is 
enabled or not for a given memory region?

I'm writting user-level communication software for a Myrinet network. I 
use Write PIO and I'm aware that WPIO performance is greatly influencied 
by the presence of write combining. Based on the performance I measured 
I can only conclude that Write Combining is enabled but I would like to 
be sure about it (since I'm planning to publish my research).

Is the default behaviour of the Linux kernel to enable write-combining? 
How can I be sure if it is enabled or not?

Thanks in advance.

__________________________
Thiago Robert
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