Hi Shimoda-san, > > > That also means, for the sys-dmac and Gen2, we then use 512 for the > > > IOMMU case and 32 (default TMIO value) for the non IOMMU case. My > > > understanding is that SYS DMAC can handle 512 in both cases. Maybe it > > > makes sense then to make an incremental patch setting the max_segs value > > > explicitly to 512 in the sys-dmac driver for Gen2? > > > > I also think SYS DMAC can handle 512 segments. However, I'm not sure > > it can improve the performance or not though. Anyway, an incremental patch > > makes sense if needed, I think. > > I measured the performance on R-Car H2 Lager. It seems 512 segments improve > the sequential input to 5%. May I make an incremental patch on the patch series? > What do you think? Cool! I didn't expect that much of a performance improvement. My main concern was understandable code because there was no "real reason" that we once use 32 and once 512. But if it causes even a performance improvement, even better :) Yes, an incremental patch is a good idea. Thanks for the work, Wolfram
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