From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from arrakis.dune.hu ([78.24.191.176]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1a0vxP-0000UR-9w for ath10k@lists.infradead.org; Mon, 23 Nov 2015 18:35:19 +0000 Subject: Re: [PATCH 2/2] ath10k: do not use coherent memory for tx buffers References: <1448284729-98078-1-git-send-email-nbd@openwrt.org> <1448284729-98078-2-git-send-email-nbd@openwrt.org> <56534C01.8030407@codeaurora.org> <5653549B.8090503@dd-wrt.com> <56535A23.3020804@codeaurora.org> From: Felix Fietkau Message-ID: <56535C4D.1010703@openwrt.org> Date: Mon, 23 Nov 2015 19:34:53 +0100 MIME-Version: 1.0 In-Reply-To: <56535A23.3020804@codeaurora.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "ath10k" Errors-To: ath10k-bounces+kvalo=adurom.com@lists.infradead.org To: Peter Oh , ath10k@lists.infradead.org On 2015-11-23 19:25, Peter Oh wrote: > > On 11/23/2015 10:02 AM, Sebastian Gottschall wrote: >> Am 23.11.2015 um 18:25 schrieb Peter Oh: >>> Hi, >>> >>> Have you measured the peak throughput? >>> The pre-allocated coherent memory concept was introduced as once of >>> peak throughput improvement. >>> IIRC, dma_map_single takes about 4 us on Cortex A7 and >>> dma_unmap_single also takes time to invalid cache. >>> Please share your tput number before and after, so I don't need to >>> worry about performance degrade. >> yes. and this concept fucks up the qualcom ipq806x platform (which has >> by default 2 QCA99XX cards). it does not work, since the preallocated >> concept allocates too much memory > Can you specify the number that you're seeing? > The tx buffer descriptor uses 56KB, so it would require 64KB x 2 slab > for 2 cards which is 128KB. > Are you saying your system does not work because of this 128KB usage? The reason might be the GFP_DMA flag, which is unnecessary. - Felix _______________________________________________ ath10k mailing list ath10k@lists.infradead.org http://lists.infradead.org/mailman/listinfo/ath10k