Received: by 2002:a05:7412:d8a:b0:e2:908c:2ebd with SMTP id b10csp616289rdg; Thu, 12 Oct 2023 16:05:47 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEQZqDbyUILppIj0O6YPoIUhvDjzGelgpq1edkZVIXwlL4+/46cnN5C1tJP05bl4roKGRqY X-Received: by 2002:a17:90a:e2c8:b0:27c:f905:d6d0 with SMTP id fr8-20020a17090ae2c800b0027cf905d6d0mr7374663pjb.24.1697151947225; Thu, 12 Oct 2023 16:05:47 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1697151947; cv=none; d=google.com; s=arc-20160816; b=FPLIpKGuyf6UNKAhdnU5aIr0N0Gj/YeSd3t+YYAzdP9L+wJBphAfbxG0AjzAJhTsFL DHGKy7Fl7XgVAt8qDDZiCQXixyUAbdktVp6dL4MkeFYl+bE+yFaS26sr669we5q50Vy9 v6meTHP7TIx0iC2Vi4zaC2uvJOR1wUJKgpXbJqZyXpDdsl/tE67GgANYIRymYpNgVbp4 dOwAKGsduT8MhrFwTwvHU7KYR90vALgJUyMxmhQuF8f3yKW/4nn7aeH8FA611rEkmW1l /anNtUxqRVMA9rGPgfDyK30V+Aq0bEDm8cthbs9hl2sxvnAGhqu4j+ZNPThhLqnErEFP 0mvA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:dkim-signature; bh=MjY6Bfa7hXy3EtsVkBFJvcxDVqkLy8yAMFEk0tgy2ww=; fh=QJSWK5xJz4gqiMZWdcUxnnS3CWLmK18xqITVklAvPVU=; b=j0ck9dnM1oytDKUv4dpmXHv+PcVlUtgMRScgYNkULbUuJTwQAjM8unOUFD4SlKhB58 nxYmU01KQ51Sax3xX+hKrRFSNNaLUhoNmqyd7KwaP+w3ZVskIGaDAZPreecpzCdADNEH Tsv/ZeM2oVnPgSXr35odo5hi1cNPWMuRo0d8pyH8YGVcGeYkjkC+KLn+AEQ0UCckxe7b PoExDgwrxGFWYoighXCMBAXy2cVZoA/huGQYv+9EUfqjAPlPNrrIqfbwZEdOM3GSla75 DeXnQmTWri4Kyz8kE8ng02kAUV5lgtN1LaScaI0toI8Y89VU9TdyI9pstxzh3wGj7SXH phmw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=FwKxfCOR; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Return-Path: Received: from howler.vger.email (howler.vger.email. [2620:137:e000::3:4]) by mx.google.com with ESMTPS id ca23-20020a056a02069700b0057759a5b7dasi3909315pgb.827.2023.10.12.16.05.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Oct 2023 16:05:47 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) client-ip=2620:137:e000::3:4; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=FwKxfCOR; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by howler.vger.email (Postfix) with ESMTP id D8044829F667; Thu, 12 Oct 2023 16:05:44 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at howler.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1443055AbjJLXFY (ORCPT + 99 others); Thu, 12 Oct 2023 19:05:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1443052AbjJLXFX (ORCPT ); Thu, 12 Oct 2023 19:05:23 -0400 Received: from mail-pf1-x430.google.com (mail-pf1-x430.google.com [IPv6:2607:f8b0:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90CE6E7 for ; Thu, 12 Oct 2023 16:04:57 -0700 (PDT) Received: by mail-pf1-x430.google.com with SMTP id d2e1a72fcca58-693400e09afso358086b3a.1 for ; Thu, 12 Oct 2023 16:04:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697151897; x=1697756697; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=MjY6Bfa7hXy3EtsVkBFJvcxDVqkLy8yAMFEk0tgy2ww=; b=FwKxfCORdKGCkpYs8q/7h2nm6KnkQSHSDBLJd3Hu3X5dZAY26gZjPKl7hdPgBf2PXY Yb8bWtg/9elAzYL+qyKwJmffHvQNsekkiWAlCdC1f1XIW8DlXTF58HBT1p0oRtCTcOGn 9g973lk7zBbvl+9zhnrwg/ZlpUWbp+9iuA6CEHm/WaJ6qxTEKluaigA20REqhOUmlsi2 3Bk1v3mDyuiz+UflRIHaIvM9TEkkdWUiLnAzvDMT++RtwmIsyGXDtLqKOnQrvkKcnGkj 7wb72gqCs2IxaI7dIHUYNBL+h+YEP3SLKFfYEh3iVOsuXFlfJEAvAGsEsUsvud3eI1ww dznA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697151897; x=1697756697; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=MjY6Bfa7hXy3EtsVkBFJvcxDVqkLy8yAMFEk0tgy2ww=; b=He5R1br+iB66bmPSJufwwWvWDzgN1+V885mekdvisqtSC91Y+B8pVD8mSlAPhD8RD/ 67MPE0O/LQbFKui6UrIefqdwW0qy5wjivKMJbpA9VtySZ5mhyzFBn9GRG9PV07Mzgdsq Q+U0zNTQ7SueC9rcXdGEucFVkipZ/jMaIV7IAa9YnJIDfvk6PGZAzgTL40X/Bf3hzITV y1efpf05JgIxa3kJ/NMvcZkdNRS1cvIZBxYvLJUUQbhnEVjOUDe/c0TdpVh0e0VyqBpD OH7W6qfr1w5l1Ev7YsQ/KbvyhzW+aMrZ2nRFi0fuF3pQ1ElHIOvKQyW6O3jLmcXg6rMQ 1UHA== X-Gm-Message-State: AOJu0YziaBQ5C5XRUqLUy6XIpCwV4QJk/i0ttaJQQM05UK940mZCsY+P TNXeQkCehP5v93Ud5sAyAIk= X-Received: by 2002:a05:6a00:2e92:b0:692:b3d4:e6c3 with SMTP id fd18-20020a056a002e9200b00692b3d4e6c3mr27619108pfb.0.1697151896807; Thu, 12 Oct 2023 16:04:56 -0700 (PDT) Received: from localhost.localdomain ([140.116.154.65]) by smtp.gmail.com with ESMTPSA id e4-20020a62ee04000000b006889664aa6csm12193998pfi.5.2023.10.12.16.04.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Oct 2023 16:04:55 -0700 (PDT) From: Kuan-Wei Chiu To: zhenyuw@linux.intel.com, zhi.a.wang@intel.com Cc: jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, tvrtko.ursulin@linux.intel.com, airlied@gmail.com, daniel@ffwll.ch, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Kuan-Wei Chiu Subject: [PATCH] drm/i915/gvt: Optimize mmio_offset_compare() for efficiency Date: Fri, 13 Oct 2023 07:04:49 +0800 Message-Id: <20231012230449.2109078-1-visitorckw@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on howler.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Thu, 12 Oct 2023 16:05:45 -0700 (PDT) The original code used conditional branching in the mmio_offset_compare function to compare two values and return -1, 1, or 0 based on the result. However, the list_sort comparison function only needs results <0, >0, or =0. This patch optimizes the code to make the comparison branchless, improving efficiency and reducing code size. This change reduces the number of comparison operations from 1-2 to a single subtraction operation, thereby saving the number of instructions. Signed-off-by: Kuan-Wei Chiu --- drivers/gpu/drm/i915/gvt/debugfs.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/debugfs.c b/drivers/gpu/drm/i915/gvt/debugfs.c index baccbf1761b7..998d82a259c8 100644 --- a/drivers/gpu/drm/i915/gvt/debugfs.c +++ b/drivers/gpu/drm/i915/gvt/debugfs.c @@ -48,11 +48,7 @@ static int mmio_offset_compare(void *priv, ma = container_of(a, struct diff_mmio, node); mb = container_of(b, struct diff_mmio, node); - if (ma->offset < mb->offset) - return -1; - else if (ma->offset > mb->offset) - return 1; - return 0; + return ma->offset - mb->offset; } static inline int mmio_diff_handler(struct intel_gvt *gvt, -- 2.25.1