Messages in this thread | | | Date | Thu, 4 Jul 2019 16:06:35 +0300 | From | Ilias Apalodimas <> | Subject | Re: [PATCH net-next 3/3] net: stmmac: Introducing support for Page Pool |
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Hi Jose,
> Thank you all for your review comments ! > > From: Ilias Apalodimas <ilias.apalodimas@linaro.org> > > > That's why i was concerned on what will happen on > 1000b frames and what the > > memory pressure is going to be. > > The trade off here is copying vs mapping/unmapping. > > Well, the performance numbers I mentioned are for TSO with default MTU > (1500) and using iperf3 with zero-copy. Here follows netperf: >
Ok i guess this should be fine. Here's why. You'll allocate an extra memory from page pool API which equals the number of descriptors * 1 page. You also allocate SKB's to copy the data and recycle the page pool buffers. So page_pool won't add any significant memory pressure since we expect *all* it's buffers to be recycled. The SKBs are allocated anyway in the current driver so bottom line you trade off some memory (the page_pool buffers) + a memcpy per packet and skip the dma map/unmap which is the bottleneck in your hardware. I think it's fine
Cheers /Ilias
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