Messages in this thread | | | Date | Sun, 27 Oct 2013 20:01:48 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH] X86: MM: Add PAT Type write-through in combination with mtrr |
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On Sun, Oct 27, 2013 at 06:56:08PM +0100, Andreas Werner wrote: > Transmit Buffers WC (only write to that buffer) > i have PICe bursts on my tracer.
For that you can do ioremap_wc().
> Receive Buffers WT (only read to that buffer). I use > clflush_cache_range before reading from that adresses and i have PCIe > bursts on my tracer.
That one I don't understand - why would you need a WT buffer? It only caches reads but you will read from it only once after it has been received. Why pollute the cache?
IOW, you probably could use a WC buffer here too, as it would combine the writes coming from the FPGA.
Btw, there's also mtrr_add(..., MTRR_TYPE_WRTHROUGH, ) if you must use a WT thing. Have you tried that?
> With UC memory there are no PCIe bursts and my bandwidth is very slow.
Right.
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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