From 6b58e0a5f32dedb609438bb9c9c82aa6e23381f2 Mon Sep 17 00:00:00 2001 From: Fan Du Date: Fri, 6 Mar 2015 11:18:23 +0800 Subject: ipv4: Use binary search to choose tcp PMTU probe_size Current probe_size is chosen by doubling mss_cache, the probing process will end shortly with a sub-optimal mss size, and the link mtu will not be taken full advantage of, in return, this will make user to tweak tcp_base_mss with care. Use binary search to choose probe_size in a fine granularity manner, an optimal mss will be found to boost performance as its maxmium. In addition, introduce a sysctl_tcp_probe_threshold to control when probing will stop in respect to the width of search range. Test env: Docker instance with vxlan encapuslation(82599EB) iperf -c 10.0.0.24 -t 60 before this patch: 1.26 Gbits/sec After this patch: increase 26% 1.59 Gbits/sec Signed-off-by: Fan Du Acked-by: John Heffner Signed-off-by: David S. Miller --- net/ipv4/sysctl_net_ipv4.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'net/ipv4/sysctl_net_ipv4.c') diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index d151539da8e6..d3c09c12ee81 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -883,6 +883,13 @@ static struct ctl_table ipv4_net_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "tcp_probe_threshold", + .data = &init_net.ipv4.sysctl_tcp_probe_threshold, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, { } }; -- cgit From 05cbc0db03e82128f2e7e353d4194dd24a1627fe Mon Sep 17 00:00:00 2001 From: Fan Du Date: Fri, 6 Mar 2015 11:18:24 +0800 Subject: ipv4: Create probe timer for tcp PMTU as per RFC4821 As per RFC4821 7.3. Selecting Probe Size, a probe timer should be armed once probing has converged. Once this timer expired, probing again to take advantage of any path PMTU change. The recommended probing interval is 10 minutes per RFC1981. Probing interval could be sysctled by sysctl_tcp_probe_interval. Eric Dumazet suggested to implement pseudo timer based on 32bits jiffies tcp_time_stamp instead of using classic timer for such rare event. Signed-off-by: Fan Du Signed-off-by: David S. Miller --- net/ipv4/sysctl_net_ipv4.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'net/ipv4/sysctl_net_ipv4.c') diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index d3c09c12ee81..fdf899163d44 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -890,6 +890,13 @@ static struct ctl_table ipv4_net_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "tcp_probe_interval", + .data = &init_net.ipv4.sysctl_tcp_probe_interval, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, { } }; -- cgit From 51456b2914a34d16b1255b7c55d5cbf6a681d306 Mon Sep 17 00:00:00 2001 From: Ian Morris Date: Fri, 3 Apr 2015 09:17:26 +0100 Subject: ipv4: coding style: comparison for equality with NULL The ipv4 code uses a mixture of coding styles. In some instances check for NULL pointer is done as x == NULL and sometimes as !x. !x is preferred according to checkpatch and this patch makes the code consistent by adopting the latter form. No changes detected by objdiff. Signed-off-by: Ian Morris Signed-off-by: David S. Miller --- net/ipv4/sysctl_net_ipv4.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'net/ipv4/sysctl_net_ipv4.c') diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index fdf899163d44..c3852a7ff3c7 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -909,7 +909,7 @@ static __net_init int ipv4_sysctl_init_net(struct net *net) int i; table = kmemdup(table, sizeof(ipv4_net_table), GFP_KERNEL); - if (table == NULL) + if (!table) goto err_alloc; /* Update the variables to point into the current struct net */ @@ -918,7 +918,7 @@ static __net_init int ipv4_sysctl_init_net(struct net *net) } net->ipv4.ipv4_hdr = register_net_sysctl(net, "net/ipv4", table); - if (net->ipv4.ipv4_hdr == NULL) + if (!net->ipv4.ipv4_hdr) goto err_reg; net->ipv4.sysctl_local_reserved_ports = kzalloc(65536 / 8, GFP_KERNEL); @@ -956,7 +956,7 @@ static __init int sysctl_ipv4_init(void) struct ctl_table_header *hdr; hdr = register_net_sysctl(&init_net, "net/ipv4", ipv4_table); - if (hdr == NULL) + if (!hdr) return -ENOMEM; if (register_pernet_subsys(&ipv4_sysctl_ops)) { -- cgit