From patchwork Tue Apr 16 06:16:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Long Li X-Patchwork-Id: 13631333 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CE8543C08A; Tue, 16 Apr 2024 06:17:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713248233; cv=none; b=Ip6NU5Al1ZuAYo5NF17B3OmT1fcIaHI7O1wm3JTJTR1DXQa7k9Pd/2pX4yk5tg0wLKLheW31V2DmIKi/U8aLtXvdl5wn6WTOZuAyFIgWdp7Ffo24cQ0xMfNzqAAcNZ1KPqgMY2guAwFfHGCQMED5m4N5+1AGy7vSdqWtnuRymsc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713248233; c=relaxed/simple; bh=gJQU4Bkk4LOP5HF/9EDNIiyhoNs7Y26nmkx+uVMNmyk=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Xj4DSLBEaFb6XgWUgFTnN/D4t+ccH9mkOVjks0zFJN1QJ+Vi+fn96SGOqmHft9K9v2KuGvst4FzJZELOxkUONjZoUZYNwykPIcraHaU4rNlTFomvrtO4OWt3gjnr8Py4UYPPm0DVzXNFIruZRoEZk7Zn1izPrxRBfAAWjNL2hpk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.252]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4VJYdP4rLYzXlMb; Tue, 16 Apr 2024 14:13:45 +0800 (CST) Received: from kwepemi500009.china.huawei.com (unknown [7.221.188.199]) by mail.maildlp.com (Postfix) with ESMTPS id AA9B018006D; Tue, 16 Apr 2024 14:17:02 +0800 (CST) Received: from localhost.localdomain (10.175.127.227) by kwepemi500009.china.huawei.com (7.221.188.199) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Tue, 16 Apr 2024 14:17:01 +0800 From: Long Li To: , CC: , , , , , Subject: [PATCH v2] xarray: inline xas_descend to improve performance Date: Tue, 16 Apr 2024 14:16:28 +0800 Message-ID: <20240416061628.3768901-1-leo.lilong@huawei.com> X-Mailer: git-send-email 2.31.1 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemi500009.china.huawei.com (7.221.188.199) The commit 63b1898fffcd ("XArray: Disallow sibling entries of nodes") modified the xas_descend function in such a way that it was no longer being compiled as an inline function, because it increased the size of xas_descend(), and the compiler no longer optimizes it as inline. This had a negative impact on performance, xas_descend is called frequently to traverse downwards in the xarray tree, making it a hot function. Inlining xas_descend has been shown to significantly improve performance by approximately 4.95% in the iozone write test. Machine: Intel(R) Xeon(R) Gold 6240 CPU @ 2.60GHz #iozone i 0 -i 1 -s 64g -r 16m -f /test/tmptest Before this patch: kB reclen write rewrite read reread 67108864 16384 2230080 3637689 6315197 5496027 After this patch: kB reclen write rewrite read reread 67108864 16384 2340360 3666175 6272401 5460782 Percentage change: 4.95% 0.78% -0.68% -0.64% This patch introduces inlining to the xas_descend function. While this change increases the size of lib/xarray.o, the performance gains in critical workloads make this an acceptable trade-off. Size comparison before and after patch: .text .data .bss file 0x3502 0 0 lib/xarray.o.before 0x3602 0 0 lib/xarray.o.after Signed-off-by: Long Li --- v2: - Using '__always_inline' instead of 'inline' guarantees that xas_descend will definitely be inlined. lib/xarray.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/xarray.c b/lib/xarray.c index fbf1d1dd83bc..84faa433cd24 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -200,7 +200,8 @@ static void *xas_start(struct xa_state *xas) return entry; } -static void *xas_descend(struct xa_state *xas, struct xa_node *node) +static __always_inline void *xas_descend(struct xa_state *xas, + struct xa_node *node) { unsigned int offset = get_offset(xas->xa_index, node); void *entry = xa_entry(xas->xa, node, offset);