From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31486C433E1 for ; Mon, 22 Jun 2020 17:32:56 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1402320767 for ; Mon, 22 Jun 2020 17:32:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1402320767 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id E49E08919B; Mon, 22 Jun 2020 17:32:55 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wIMNR0FUnhiI; Mon, 22 Jun 2020 17:32:55 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 60B0588DA6; Mon, 22 Jun 2020 17:32:55 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 26CF9C0891; Mon, 22 Jun 2020 17:32:55 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id C822AC016F for ; Mon, 22 Jun 2020 17:32:53 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id B4F4B8918B for ; Mon, 22 Jun 2020 17:32:53 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DBuEO3YUpSMI for ; Mon, 22 Jun 2020 17:32:51 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from huawei.com (szxga07-in.huawei.com [45.249.212.35]) by hemlock.osuosl.org (Postfix) with ESMTPS id AB2C888DA6 for ; Mon, 22 Jun 2020 17:32:51 +0000 (UTC) Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 791CB6476C5AEFFEEC27; Tue, 23 Jun 2020 01:32:48 +0800 (CST) Received: from localhost.localdomain (10.69.192.58) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Tue, 23 Jun 2020 01:32:39 +0800 From: John Garry To: , Subject: [PATCH 0/4] iommu/arm-smmu-v3: Improve cmdq lock efficiency Date: Tue, 23 Jun 2020 01:28:36 +0800 Message-ID: <1592846920-45338-1-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-CFilter-Loop: Reflected Cc: trivial@kernel.org, maz@kernel.org, linuxarm@huawei.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" As mentioned in [0], the CPU may consume many cycles processing arm_smmu_cmdq_issue_cmdlist(). One issue we find is the cmpxchg() loop to get space on the queue takes approx 25% of the cycles for this function. This series removes that cmpxchg(). For my NVMe test with 3x NVMe SSDs, I'm getting a ~24% throughput increase: Before: 1310 IOPs After: 1630 IOPs I also have a test harness to check the rate of DMA map+unmaps we can achieve: CPU count 32 64 128 Before: 63187 19418 10169 After: 93287 44789 15862 (unit is map+unmaps per CPU per second) [0] https://lore.kernel.org/linux-iommu/B926444035E5E2439431908E3842AFD24B86DB@DGGEMI525-MBS.china.huawei.com/T/#ma02e301c38c3e94b7725e685757c27e39c7cbde3 John Garry (4): iommu/arm-smmu-v3: Fix trivial typo iommu/arm-smmu-v3: Calculate bits for prod and owner iommu/arm-smmu-v3: Always issue a CMD_SYNC per batch iommu/arm-smmu-v3: Remove cmpxchg() in arm_smmu_cmdq_issue_cmdlist() drivers/iommu/arm-smmu-v3.c | 233 +++++++++++++++++++++++------------- 1 file changed, 151 insertions(+), 82 deletions(-) -- 2.26.2 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu