From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [RFC] avoid indirect calls for DMA direct mappings v2 Date: Sat, 8 Dec 2018 17:50:58 +0100 Message-ID: <20181208165058.GA14874@lst.de> References: <20181207190720.18517-1-hch@lst.de> <20181208170648.296fb8a1@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181208170648.296fb8a1@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Jesper Dangaard Brouer Cc: Christoph Hellwig , iommu@lists.linux-foundation.org, Linus Torvalds , Tariq Toukan , Ilias Apalodimas , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , Robin Murphy , Konrad Rzeszutek Wilk , Tony Luck , Fenghua Yu , Marek Szyprowski , Keith Busch , Jonathan Derrick , linux-pci@vger.kernel.org, linux-ia64@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org List-Id: iommu@lists.linux-foundation.org On Sat, Dec 08, 2018 at 05:06:48PM +0100, Jesper Dangaard Brouer wrote: > You can add my: > Tested-by: Jesper Dangaard Brouer > or > Acked-by: Jesper Dangaard Brouer > > I'm very happy that you work on this. And I've done micro-benchmark > testing of the patchset (and branch dma-direct-calls), which I've made > avail here: > https://github.com/xdp-project/xdp-project/blob/master/areas/dma/dma01_test_hellwig_direct_dma.org > > My XDP performance is back, minus the BPF-indirect call, and > net_rx_action napi->poll, and net_device->ndo_xdp_xmit calls. I > verified that manually disabling retpoline for these remaining netstack > retpoline-calls restore the performance full (well minus 1.5 nanosec). Thanks a lot for all the testing (and the initial report). I'd love to still gets this in for 4.21 if we can, but for that I'd need a lot more folks to carefull review it, especially the swiotlb and ia64 bits. So if we don't get that early next week I feel we might have to punt it to the next merge window.