From patchwork Fri Oct 21 06:45:10 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mihai Maruseac X-Patchwork-Id: 120948 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 66B36B6F91 for ; Fri, 21 Oct 2011 17:45:52 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751717Ab1JUGp2 (ORCPT ); Fri, 21 Oct 2011 02:45:28 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:36612 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750933Ab1JUGp1 (ORCPT ); Fri, 21 Oct 2011 02:45:27 -0400 Received: by bkbzt19 with SMTP id zt19so4477536bkb.19 for ; Thu, 20 Oct 2011 23:45:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=KJrm6wWqzZuAUqRNtOqlaIZxFzxP/22wTK6Y6towXHM=; b=vIPUCyQLAUt4+I6WNHBTvbDooTFsiDegbNgHP9VqjEpyG6yWT/MxtRbHz4NLZ9E9xI hEbHMBOXTtiOsnnsDaU1/Orit8PyJwvMpu8ZH4vReyhBWR+bFKsZq+gCMKgoWzJg6yux XPNglm5uE+FETIO/ZbHmqz6me41x6hwRIqeVU= Received: by 10.223.63.206 with SMTP id c14mr23002888fai.7.1319179525735; Thu, 20 Oct 2011 23:45:25 -0700 (PDT) Received: from localhost.localdomain (ixro-out-rtc.ixiacom.com. [92.87.192.98]) by mx.google.com with ESMTPS id r24sm15789559faa.8.2011.10.20.23.45.23 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 20 Oct 2011 23:45:24 -0700 (PDT) From: Mihai Maruseac To: davem@davemloft.net, shemminger@vyatta.com, eric.dumazet@gmail.com Cc: mirq-linux@rere.qmqm.pl, therbert@google.com, jpirko@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, dbaluta@ixiacom.com, Mihai Maruseac Subject: [PATCH] dev: use name hash for dev_seq_ops Date: Fri, 21 Oct 2011 09:45:10 +0300 Message-Id: <1319179510-10715-1-git-send-email-mmaruseac@ixiacom.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1319097717-14910-1-git-send-email-mmaruseac@ixiacom.com> References: <1319097717-14910-1-git-send-email-mmaruseac@ixiacom.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Instead of using the dev->next chain and trying to resync at each call to dev_seq_start, use the name hash, keeping the bucket and the offset in seq->private field. Tests revealed the following results for ifconfig > /dev/null * 1000 interfaces: * 0.114s without patch * 0.089s with patch * 3000 interfaces: * 0.489s without patch * 0.110s with patch * 5000 interfaces: * 1.363s without patch * 0.250s with patch * 128000 interfaces (other setup): * ~100s without patch * ~30s with patch Signed-off-by: Mihai Maruseac Signed-off-by: Eric Dumazet --- net/core/dev.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++---------- 1 files changed, 69 insertions(+), 15 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 70ecb86..6edbcc5 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4041,6 +4041,60 @@ static int dev_ifconf(struct net *net, char __user *arg) } #ifdef CONFIG_PROC_FS + +#define BUCKET_SPACE (32 - NETDEV_HASHBITS) + +struct dev_iter_state { + struct seq_net_private p; + unsigned int pos; /* bucket << BUCKET_SPACE + offset */ +}; + +#define get_bucket(x) ((x) >> BUCKET_SPACE) +#define get_offset(x) ((x) & ((1 << BUCKET_SPACE) - 1)) +#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o)) + +static inline struct net_device *dev_from_same_bucket(struct seq_file *seq) +{ + struct dev_iter_state *state = seq->private; + struct net *net = seq_file_net(seq); + struct net_device *dev; + struct hlist_node *p; + struct hlist_head *h; + unsigned int count, bucket, offset; + + bucket = get_bucket(state->pos); + offset = get_offset(state->pos); + h = &net->dev_name_head[bucket]; + count = 0; + hlist_for_each_entry_rcu(dev, p, h, name_hlist) { + if (count++ == offset) { + state->pos = set_bucket_offset(bucket, count); + return dev; + } + } + + return NULL; +} + +static inline struct net_device *dev_from_new_bucket(struct seq_file *seq) +{ + struct dev_iter_state *state = seq->private; + struct net_device *dev; + unsigned int bucket; + + bucket = get_bucket(state->pos); + do { + dev = dev_from_same_bucket(seq); + if (dev) + return dev; + + bucket++; + state->pos = set_bucket_offset(bucket, 0); + } while (bucket < NETDEV_HASHENTRIES); + + return NULL; +} + /* * This is invoked by the /proc filesystem handler to display a device * in detail. @@ -4048,33 +4102,33 @@ static int dev_ifconf(struct net *net, char __user *arg) void *dev_seq_start(struct seq_file *seq, loff_t *pos) __acquires(RCU) { - struct net *net = seq_file_net(seq); - loff_t off; - struct net_device *dev; + struct dev_iter_state *state = seq->private; rcu_read_lock(); if (!*pos) return SEQ_START_TOKEN; - off = 1; - for_each_netdev_rcu(net, dev) - if (off++ == *pos) - return dev; + /* check for end of the hash */ + if (state->pos == 0 && *pos > 1) + return NULL; - return NULL; + return dev_from_new_bucket(seq); } void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos) { - struct net_device *dev = v; + struct net_device *dev; + + ++*pos; if (v == SEQ_START_TOKEN) - dev = first_net_device_rcu(seq_file_net(seq)); - else - dev = next_net_device_rcu(dev); + return dev_from_new_bucket(seq); - ++*pos; - return dev; + dev = dev_from_same_bucket(seq); + if (dev) + return dev; + + return dev_from_new_bucket(seq); } void dev_seq_stop(struct seq_file *seq, void *v) @@ -4173,7 +4227,7 @@ static const struct seq_operations dev_seq_ops = { static int dev_seq_open(struct inode *inode, struct file *file) { return seq_open_net(inode, file, &dev_seq_ops, - sizeof(struct seq_net_private)); + sizeof(struct dev_iter_state)); } static const struct file_operations dev_seq_fops = {