From: Gao Feng <gfree.w...@vip.163.com>
There are two spots which invoke the sock_rps_record_flow_hash, one is
sock_rps_record_flow which has already checked rfs_needed. But the other
is tun_flow_update which doesn't check if the rfs is enabled.
Now rename the original function sock_rps_record_flow_hash to
_sock_rps_record_flow_hash, and add one helper func which checks the
rfs_needed.
The perf result of two functions is following.
When rfs is disabled, it could enhance 58% performance with checking
rfs_needed.
When rfs is enabled, the performanc is lower than current about 29%.
Because the RFS is disabled by default. I think it is useful to tun
driver.
The follow is test statistics.
test_rfs_check_rfs_key invokes _sock_rps_record_flow_hash 10000000 times.
test_rfs_no_check_rfs_key invokes sock_rps_record_flow_hash 10000000 times
too.
The test function is running with bh disabled, and the cycles is measured
by rdtscll.
[ 1716.374630] rfs_needed:1
[ 1716.388961] test_rfs_check_rfs_key costs 37119844 cycles
[ 1716.404495] test_rfs_check_rfs_key costs 40229886 cycles
[ 1716.419033] test_rfs_check_rfs_key costs 37668179 cycles
[ 1716.432618] test_rfs_no_check_rfs_key costs 35181759 cycles
[ 1716.443151] test_rfs_no_check_rfs_key costs 27290206 cycles
[ 1716.453496] test_rfs_no_check_rfs_key costs 26797500 cycles
[ 2635.215760] rfs_needed:0
[ 2635.219079] test_rfs_check_rfs_key costs 8455450 cycles
[ 2635.222381] test_rfs_check_rfs_key costs 8556322 cycles
[ 2635.225761] test_rfs_check_rfs_key costs 8758388 cycles
[ 2635.232230] test_rfs_no_check_rfs_key costs 16762130 cycles
[ 2635.239942] test_rfs_no_check_rfs_key costs 19982679 cycles
[ 2635.249172] test_rfs_no_check_rfs_key costs 23894840 cycles
Signed-off-by: Gao Feng <gfree.w...@vip.163.com>
---
include/net/sock.h | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 3467d9e..584bb9a 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -910,7 +910,7 @@ static inline void sk_incoming_cpu_update(struct sock *sk)
sk->sk_incoming_cpu = raw_smp_processor_id();
}
-static inline void sock_rps_record_flow_hash(__u32 hash)
+static inline void _sock_rps_record_flow_hash(__u32 hash)
{
#ifdef CONFIG_RPS
struct rps_sock_flow_table *sock_flow_table;
@@ -922,6 +922,14 @@ static inline void sock_rps_record_flow_hash(__u32 hash)
#endif
}
+static inline void sock_rps_record_flow_hash(__u32 hash)
+{
+#ifdef CONFIG_RPS
+ if (static_key_false(&rfs_needed))
+ _sock_rps_record_flow_hash(hash);
+#endif
+}
+
static inline void sock_rps_record_flow(const struct sock *sk)
{
#ifdef CONFIG_RPS
@@ -937,7 +945,7 @@ static inline void sock_rps_record_flow(const struct sock
*sk)
* [1] : sk_state and sk_prot are in the same cache line.
*/
if (sk->sk_state == TCP_ESTABLISHED)
- sock_rps_record_flow_hash(sk->sk_rxhash);
+ _sock_rps_record_flow_hash(sk->sk_rxhash);
}
#endif
}
--
1.9.1
