From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755003AbbJHIy1 (ORCPT ); Thu, 8 Oct 2015 04:54:27 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:51044 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754084AbbJHIyX (ORCPT ); Thu, 8 Oct 2015 04:54:23 -0400 From: Arnd Bergmann To: Rameshwar Prasad Sahu Cc: vinod.koul@intel.com, dan.j.williams@intel.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, jcm@redhat.com, patches@apm.com Subject: Re: [PATCH] dmaengine: xgene-dma: Disable memcpy operation due to performance drop Date: Thu, 08 Oct 2015 10:53:54 +0200 Message-ID: <57007053.YYaOe8h6ng@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1444292716-1877-1-git-send-email-rsahu@apm.com> References: <1444292716-1877-1-git-send-email-rsahu@apm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:cTmnv5pmwh7IapU5Vw3mAxfZFgPTY5JJER5DkmrltgG573PyvRb 8UTRJ6+bImy2NDnnTmEmjA3PsP/NcGNDN/CrnR7d4mXpmt8IwaSW13zMgZSEhvpT5iogjIp 0r1LwsNiNgn5xp6ow0vVByVfF9M5/W3jcJdgjqKSyri6lQePOWrBQzveUq+mGLCYexlk/ac it2jkeDDxfdO5tN/LjFfA== X-UI-Out-Filterresults: notjunk:1;V01:K0:cT9aZELpQxU=:Sxx/kHxhMqZPighHTTbaX1 ihqUU5sxtLj6Su9/g849Dp+DFLlzueskOj6+Fe/XeQ+om4KOimyieob2G/UvWeHLAloC7/3mS iwHMhsvshKIp1uKPJrZrD31oJtOTPTRIvPo1ydDVoicAQ6UCI+md+oSP4ZE/d+EarAO3ytiMb AQAKSbQUNd5hkbid2hqkoFKu0/r+tXPzQEqa/fYX9XsRbWSbW8BwtDi5EcZpl6Gp4kLerMmCy ahl68kHWrJRklzySwXVSYADCCLYVVFXcWLu090XeDr9K8DHMJSzSuwHyciyPKQHknEKLnDgK1 k0/g47QqFnp31ogdaxwj87yd2hUgZf2Mv/LSHuKSdE1jg4/SoDQ+8UKQHaY4/cpTQqvcsaSF8 4frdqoSsNaGqzYrsKpis/9Hu+YUgMEk5grlCYwmTt30Ypr5AwVCxwQMzbId1sP5JY3rKi4GqW zgBBGV5kTph+6dlXBdTyw+aCp6JX9cx/h32Evx6rF7Vx25pMsGnG+rXNK0E+ajB2UK+g/g6Lj poQVqRso0z69uyodSzzot8EbUYmfOfSrivn2qIbeSt2gEXMdcZcKjVq3rU+8zSH0C9/n6GG5a r+wemYUHET7coHXPexiYwP4DKGKbCpQvxuIG4zEjjkddpsZwVjkJA7/MSWpwwHAer8CrbnUMI 9+2C/vG2WmrKHXNVsLOQAW0tJYZ7ZF1ZICHvdaG3d3XFj2/coVmJV8GiKsgEW3eCXi3g1VFT8 0sLPWzYwEXmD7lpV Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 08 October 2015 13:55:16 Rameshwar Prasad Sahu wrote: > The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other > computations. But the bandwidth of the entire DMA engine is shared > among all channels. This patch re-configures operations availability > such that one can achieve maximum performance for XOR and PQ > computation by removing the memory offload operations. > > Signed-off-by: Rameshwar Prasad Sahu > --- > drivers/dma/xgene-dma.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c > index 8d57b1b..2998fcb 100644 > --- a/drivers/dma/xgene-dma.c > +++ b/drivers/dma/xgene-dma.c > @@ -154,6 +154,7 @@ > #define XGENE_DMA_MAX_XOR_SRC 5 > #define XGENE_DMA_16K_BUFFER_LEN_CODE 0x0 > #define XGENE_DMA_INVALID_LEN_CODE 0x7800000000000000ULL > +#undef XGENE_DMA_MEMCPY_ENABLE > > /* X-Gene DMA descriptor error codes */ > #define ERR_DESC_AXI 0x01 > @@ -1707,7 +1708,9 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, > dma_cap_zero(dma_dev->cap_mask); > > /* Set DMA device capability */ > +#ifdef XGENE_DMA_MEMCPY_ENABLE > dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); > +#endif > dma_cap_set(DMA_SG, dma_dev->cap_mask); > > /* Basically here, the X-Gene SoC DMA engine channel 0 supports XOR I don't see what the #ifdef gains you here when the setting is hardcoded. Why not just remove that DMA_MEMCPY capability completely if you don't want to use it? Arnd