| Message ID | 1319179510-10715-1-git-send-email-mmaruseac@ixiacom.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
Le vendredi 21 octobre 2011 à 09:45 +0300, Mihai Maruseac a écrit : > 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. > ... > Signed-off-by: Mihai Maruseac <mmaruseac@ixiacom.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Thanks -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Mihai Maruseac <mihai.maruseac@gmail.com> Date: Fri, 21 Oct 2011 09:45:10 +0300 > 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 ... > Signed-off-by: Mihai Maruseac <mmaruseac@ixiacom.com> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 21 Oct 2011 09:45:10 +0300 Mihai Maruseac <mihai.maruseac@gmail.com> wrote: > 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 <mmaruseac@ixiacom.com> > --- > 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) > Why are all these function marked inline? They are big, hardly hot path and better to not continue the bad practice of inlining too much code. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 = {
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 <mmaruseac@ixiacom.com> --- net/core/dev.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++---------- 1 files changed, 69 insertions(+), 15 deletions(-)