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| author | Tonghao Zhang <xiangxia.m.yue@gmail.com> | 2017-07-18 09:28:06 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-07-19 23:49:39 +0300 |
| commit | c4b2bf6b4a35348fe6d1eb06928eb68d7b9d99a9 (patch) | |
| tree | a4fee7f327cb884723fcb54f03e2170c7b4ca995 /net/openvswitch/flow.h | |
| parent | c57c054eb5b1ccf230c49f736f7a018fcbc3e952 (diff) | |
| download | linux-c4b2bf6b4a35348fe6d1eb06928eb68d7b9d99a9.tar.xz | |
openvswitch: Optimize operations for OvS flow_stats.
When calling the flow_free() to free the flow, we call many times
(cpu_possible_mask, eg. 128 as default) cpumask_next(). That will
take up our CPU usage if we call the flow_free() frequently.
When we put all packets to userspace via upcall, and OvS will send
them back via netlink to ovs_packet_cmd_execute(will call flow_free).
The test topo is shown as below. VM01 sends TCP packets to VM02,
and OvS forward packtets. When testing, we use perf to report the
system performance.
VM01 --- OvS-VM --- VM02
Without this patch, perf-top show as below: The flow_free() is
3.02% CPU usage.
4.23% [kernel] [k] _raw_spin_unlock_irqrestore
3.62% [kernel] [k] __do_softirq
3.16% [kernel] [k] __memcpy
3.02% [kernel] [k] flow_free
2.42% libc-2.17.so [.] __memcpy_ssse3_back
2.18% [kernel] [k] copy_user_generic_unrolled
2.17% [kernel] [k] find_next_bit
When applied this patch, perf-top show as below: Not shown on
the list anymore.
4.11% [kernel] [k] _raw_spin_unlock_irqrestore
3.79% [kernel] [k] __do_softirq
3.46% [kernel] [k] __memcpy
2.73% libc-2.17.so [.] __memcpy_ssse3_back
2.25% [kernel] [k] copy_user_generic_unrolled
1.89% libc-2.17.so [.] _int_malloc
1.53% ovs-vswitchd [.] xlate_actions
With this patch, the TCP throughput(we dont use Megaflow Cache
+ Microflow Cache) between VMs is 1.18Gbs/sec up to 1.30Gbs/sec
(maybe ~10% performance imporve).
This patch adds cpumask struct, the cpu_used_mask stores the cpu_id
that the flow used. And we only check the flow_stats on the cpu we
used, and it is unncessary to check all possible cpu when getting,
cleaning, and updating the flow_stats. Adding the cpu_used_mask to
sw_flow struct does’t increase the cacheline number.
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/openvswitch/flow.h')
| -rw-r--r-- | net/openvswitch/flow.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h index a9bc1c875965..1875bba4f865 100644 --- a/net/openvswitch/flow.h +++ b/net/openvswitch/flow.h @@ -31,6 +31,7 @@ #include <linux/jiffies.h> #include <linux/time.h> #include <linux/flex_array.h> +#include <linux/cpumask.h> #include <net/inet_ecn.h> #include <net/ip_tunnels.h> #include <net/dst_metadata.h> @@ -219,6 +220,7 @@ struct sw_flow { */ struct sw_flow_key key; struct sw_flow_id id; + struct cpumask cpu_used_mask; struct sw_flow_mask *mask; struct sw_flow_actions __rcu *sf_acts; struct flow_stats __rcu *stats[]; /* One for each CPU. First one |