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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A312CC677F1 for ; Wed, 22 Feb 2023 14:39:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231939AbjBVOjX (ORCPT ); Wed, 22 Feb 2023 09:39:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231862AbjBVOjV (ORCPT ); Wed, 22 Feb 2023 09:39:21 -0500 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93CE838030; Wed, 22 Feb 2023 06:39:20 -0800 (PST) Received: by mail-wr1-x42f.google.com with SMTP id t15so8067841wrz.7; Wed, 22 Feb 2023 06:39:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=M22oHJnuucBcT6iKB9lxW+hMSBsBNFHqZcHQOuzIIKc=; b=ZykuQEKlBFq6ujC0ObdSGHbCSm/snEq4aV9KxuboP9EFXzEeY1U79ozyKgjFHHthmf 0hFMSfi6beUjiDTigg8SpQXuJDjkABt+JdL4wJEEh9eQIHVkcc7S47IJNmsM7P+Pg4n4 QDnxFwrpNzwPIKIEdFmw2BPWED5431FYF9tnIKllCgamReeOon8C+8hqImeyB5Of9dGK dM2Fu67Wb6NRVJGP3dLaWscF+0tEdqS0eebfY2uHxLgEdUahj9V19t+7P759MWEYrAqs ApjBt7YA37iJGalEGm2OI25QtjLMrC/rDcSSANiRzXnR4ku0lCFODiqWfW+u+udurx8+ GjAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=M22oHJnuucBcT6iKB9lxW+hMSBsBNFHqZcHQOuzIIKc=; b=x56e1uctdnxWxLNmlu4ChzRbT/OugZLTyiXrVvPHGK8gF8Y1SDUPGi0/qY7ZYIEyoQ IPaLwIoCHDGqlsvbF4I/Xe+Gpg5jfeJ+Qz3LPXLAgX0b13KThzWhkD2w5jf3UUqJCaPl zj6GsXa7jcYUiQ+E8K4bs0Og1wVMJYj6EkYIKJJp2H4JSZVfuDUBCMMC/WgB0Im+M28r Q1fGn6sv5UVM4oTARBV6NavGKrwFCQvL/x3Xt+sCG+RwKfbIkW/gpJWNw+2XVISXGYxM i4mqwYOOf/YXVeTyxqzB0lrizKJLckB6yfc/vgpT8epetSAPNUkQ0ia5Xd4+QBei8ppP RBaw== X-Gm-Message-State: AO0yUKUiJTOlVz/4T4C5c6keldw5IkhWuXavLzC9yy3IWJN8Y5JSqC8c OD+yLskNd4GFmoU+QDtJ3F4Ip9bQkSI= X-Google-Smtp-Source: AK7set+k5mgTDKfGeD1kAvandRiZgXbSjsP+KNmZB3LcQrQ94qDCi9l/6JGlG12oiZ0mFXG/9F8sxQ== X-Received: by 2002:a5d:45cb:0:b0:2c5:4f04:c50d with SMTP id b11-20020a5d45cb000000b002c54f04c50dmr7554750wrs.48.1677076758850; Wed, 22 Feb 2023 06:39:18 -0800 (PST) Received: from 127.0.0.1localhost (94.196.95.64.threembb.co.uk. [94.196.95.64]) by smtp.gmail.com with ESMTPSA id o2-20020a5d4742000000b002c59c6abc10sm8151735wrs.115.2023.02.22.06.39.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Feb 2023 06:39:18 -0800 (PST) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com, linux-kernel@vger.kernel.org Subject: [PATCH for-next 3/4] io_uring/rsrc: optimise single entry advance Date: Wed, 22 Feb 2023 14:36:50 +0000 Message-Id: X-Mailer: git-send-email 2.39.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Iterating within the first bvec entry should be essentially free, but we use iov_iter_advance() for that, which shows up in benchmark profiles taking up to 0.5% of CPU. Replace it with a hand coded version. Signed-off-by: Pavel Begunkov --- io_uring/rsrc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index 53845e496881..ebbd2cea7582 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -1364,7 +1364,10 @@ int io_import_fixed(int ddir, struct iov_iter *iter, const struct bio_vec *bvec = imu->bvec; if (offset <= bvec->bv_len) { - iov_iter_advance(iter, offset); + iter->bvec = bvec; + iter->nr_segs = bvec->bv_len; + iter->count -= offset; + iter->iov_offset = offset; } else { unsigned long seg_skip; -- 2.39.1