Merge branch 'stmmac-optimizations'
Alexandre TORGUE says: ==================== stmmac: enhance driver performances and update the version According to Giuseppe, I send the v3 series. This is a subset of patches to rework the driver in order to improve its performances and make it more robust under stress conditions. All patches have been ported on STi mainstream kernel branch and tested on ARM STiH4xx platforms and newer ones. This series also updates the driver version and prepares it to include further development to support new chips. In detail, these patches are: o to rework and improve the internal DMA bus settings Fine tuning is mandatory on some platforms for both performance and stability issues. o to rework and optimize the descriptor management. This will help a lot on performance side and preparing the inclusion on the GMAC4.x. o to add a set of optimizations for both xmit and rx functions. These will help a lot on performance side and making the driver more robust in case of low memory conditions and under some stress test, performed for example on IP-STB. Below some throughput figures obtained on some boxes before and after the patches. nuttcp (mbps) iperf (Mbps) ------------------------------------------------------------------ tcp udp tcp udp tx rx tx rx tx rx tx rx ------------------------------------------ old 680 800 480 506 760 800 600 700 new 830 880 540 630 840 880 700 800 V2: - rx_copybreak is now managed by using ethtool. V3: - improve comments on PCIe detailing that there are no regressions - rework some APIs to properly define some params as bool as expected - rework the formula to get the element inside the ring. Comparing V2, patches 4 and 13 have been merged because the same formula have been used. After this rework, no evident benefit has been noticed in terms of performances so the table above is still valid. Disassembling the code for SH4 and ARM, with the new formula just an instr is saved (depending on compiler flags) and this gives us not so relevanti gain, for example, on SH4 where some instr are executed in the same pipeline stage. Ring sizes are now fixed and maybe they can be reworked to be tuned w/o using stmmaceth= cmdline option. Indeed, nobody change these sizes and indeed the numbers selected by default respect the budget and avoid to pass invalid setup. These are the best driver default sizes for ring and chain. ====================
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