On 19/07/17 09:37, Ard Biesheuvel wrote: > On 18 July 2017 at 17:57, Robin Murphy <robin.mur...@arm.com> wrote: >> Hi all, >> >> In the wake of the ARM SMMU optimisation efforts, it seems that certain >> workloads (e.g. storage I/O with large scatterlists) probably remain quite >> heavily influenced by IOVA allocation performance. Separately, Ard also >> reported massive performance drops for a graphical desktop on AMD Seattle >> when enabling SMMUs via IORT, which we traced to dma_32bit_pfn in the DMA >> ops domain getting initialised differently for ACPI vs. DT, and exposing >> the overhead of the rbtree slow path. Whilst we could go around trying to >> close up all the little gaps that lead to hitting the slowest case, it >> seems a much better idea to simply make said slowest case a lot less slow. >> >> I had a go at rebasing Leizhen's last IOVA series[1], but ended up finding >> the changes rather too hard to follow, so I've taken the liberty here of >> picking the whole thing up and reimplementing the main part in a rather >> less invasive manner. >> >> Robin. >> >> [1] >> https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg17753.html >> >> Robin Murphy (1): >> iommu/iova: Extend rbtree node caching >> >> Zhen Lei (3): >> iommu/iova: Optimise rbtree searching >> iommu/iova: Optimise the padding calculation >> iommu/iova: Make dma_32bit_pfn implicit >> >> drivers/gpu/drm/tegra/drm.c | 3 +- >> drivers/gpu/host1x/dev.c | 3 +- >> drivers/iommu/amd_iommu.c | 7 +-- >> drivers/iommu/dma-iommu.c | 18 +------ >> drivers/iommu/intel-iommu.c | 11 ++-- >> drivers/iommu/iova.c | 112 >> ++++++++++++++++----------------------- >> drivers/misc/mic/scif/scif_rma.c | 3 +- >> include/linux/iova.h | 8 +-- >> 8 files changed, 60 insertions(+), 105 deletions(-) >> > > These patches look suspiciously like the ones I have been using over > the past couple of weeks (modulo the tegra and host1x changes) from > your git tree. They work fine on my AMD Overdrive B1, both in DT and > in ACPI/IORT modes, although it is difficult to quantify any > performance deltas on my setup.
Indeed - this is a rebase (to account for those new callers) with a couple of trivial tweaks to error paths and corner cases that normal usage shouldn't have been hitting anyway. "No longer unusably awful" is a good enough performance delta for me :) > Tested-by: Ard Biesheuvel <ard.biesheu...@linaro.org> Thanks! Robin.