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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 16CD9C31E40 for ; Tue, 6 Aug 2019 15:55:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD7922070D for ; Tue, 6 Aug 2019 15:55:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="SOWAI7kW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387470AbfHFPzY (ORCPT ); Tue, 6 Aug 2019 11:55:24 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:43923 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729638AbfHFPzY (ORCPT ); Tue, 6 Aug 2019 11:55:24 -0400 Received: by mail-oi1-f194.google.com with SMTP id w79so67351599oif.10; Tue, 06 Aug 2019 08:55:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:from:to:date:message-id:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=R4iZx0COrHfQ1YO0z4V/oENEdXcG7j+Gflb0UFePd/k=; b=SOWAI7kWYER3fLmidQaUgow0X4fneNiL6OZJyV/9OLkxBEqw0/Kl6rNh17rgrkEy7l 1u2ix7PasZJhH/Zaru8307TAG6bt6mnjJ4TIiVffVd+Sk4IwZnO1Vq2xsrKcbTvh6ZEU WgO8+jPCPMsG6XWPOw5biMdVoiXoJR+dijJSAvCpDa1AH+vPihryxHdXu+/zTmuQ9BZF bqvClpONSCXRjYda+EWIMnB+O1dQs/BbZf6stG3xdXfxR2i9NM482wD8emVbo+i0xES7 Cf05i+0v/lPCYeegyQAQ7VXUVCTF0EjYsFiTxJqxuVp3Ex9ZkP+U7avmM6w8BuJ7su29 67sg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:from:to:date:message-id :in-reply-to:references:user-agent:mime-version :content-transfer-encoding; bh=R4iZx0COrHfQ1YO0z4V/oENEdXcG7j+Gflb0UFePd/k=; b=PO3ttQ+81co3VuqxeN0dAAtZiGksO1IL24zNN5gKA9LGRtwYcJOrZ15lVxriX2EbzP u4a+yAbSs8hqd0SnUKtwTjD+nBPhsrj5GgzjGS+U5/aO9I64WpDs2KctRyEYqSjMKYGa /6O54RlNEa+KUnhquPQeqyWk2NTaTzWEa+yOtMDvrVyyxr5JenTKAnJOpMCy0z0PkDad LqyyfL3PAgG8ymDkNcBVXOrhkRL75cS7B3dKRYV5R2wCaY2mg64UQG97tTtTJuRSYJls rCZ31PpoJvKAK3piiSgB/01vlOWwLrX8V4jVbCTYx6WcrmnmDcLRpeiQQG+W4fe3rfww x+xA== X-Gm-Message-State: APjAAAXlLweJdgEYhsGKoniLDoj6OK+C7NtHdvIOG7PCT2v5JaREKEVJ /Y79VI0awXUA92WVbAkncOO9uRgo X-Google-Smtp-Source: APXvYqypW7oPGNDiTEPOmZFPfV55NcSDm8ju3LuO+SazAoV77Y/lUPdUJ/winVbw9O0+20UCje/3YQ== X-Received: by 2002:a02:a703:: with SMTP id k3mr4860732jam.12.1565106923170; Tue, 06 Aug 2019 08:55:23 -0700 (PDT) Received: from gateway.1015granger.net (c-68-61-232-219.hsd1.mi.comcast.net. [68.61.232.219]) by smtp.gmail.com with ESMTPSA id k3sm468949ioq.18.2019.08.06.08.55.22 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 06 Aug 2019 08:55:22 -0700 (PDT) Received: from manet.1015granger.net (manet.1015granger.net [192.168.1.51]) by gateway.1015granger.net (8.14.7/8.14.7) with ESMTP id x76FtMmu011565; Tue, 6 Aug 2019 15:55:22 GMT Subject: [PATCH v1 18/18] xprtrdma: Optimize rpcrdma_post_recvs() From: Chuck Lever To: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Tue, 06 Aug 2019 11:55:22 -0400 Message-ID: <20190806155521.9529.80398.stgit@manet.1015granger.net> In-Reply-To: <20190806155246.9529.14571.stgit@manet.1015granger.net> References: <20190806155246.9529.14571.stgit@manet.1015granger.net> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Micro-optimization: In rpcrdma_post_recvs, since commit e340c2d6ef2a ("xprtrdma: Reduce the doorbell rate (Receive)"), the common case is to return without doing anything. Found with perf. Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/verbs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 4112b8a..36e840b 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1457,7 +1457,7 @@ static void rpcrdma_regbuf_free(struct rpcrdma_regbuf *rb) count = 0; needed = buf->rb_credits + (buf->rb_bc_srv_max_requests << 1); - if (ep->rep_receive_count > needed) + if (likely(ep->rep_receive_count > needed)) goto out; needed -= ep->rep_receive_count; if (!temp)