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Message-Id: <20240723135742.35102-1-kerneljasonxing@gmail.com>
Date: Tue, 23 Jul 2024 21:57:42 +0800
From: Jason Xing <kerneljasonxing@...il.com>
To: davem@...emloft.net,
edumazet@...gle.com,
kuba@...nel.org,
pabeni@...hat.com,
horms@...nel.org
Cc: netdev@...r.kernel.org,
Jason Xing <kernelxing@...cent.com>
Subject: [RFC PATCH net-next] net: add an entry for CONFIG_NET_RX_BUSY_POLL
From: Jason Xing <kernelxing@...cent.com>
When I was doing performance test on unix_poll(), I found out that
accessing sk->sk_ll_usec when calling sock_poll()->sk_can_busy_loop()
occupies too much time, which causes around 16% degradation. So I
decided to turn off this config, which cannot be done apparently
before this patch.
Signed-off-by: Jason Xing <kernelxing@...cent.com>
---
More data not much related if you're interested:
5.82 │ mov 0x18(%r13),%rdx
0.03 │ mov %rsi,%r12
1.76 │ mov %rdi,%rbx
│ sk_can_busy_loop():
0.50 │ mov 0x104(%rdx),%r14d
41.30 │ test %r14d,%r14d
Note: I run 'perf record -e L1-dcache-load-misses' to diagnose
---
net/Kconfig | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/Kconfig b/net/Kconfig
index d27d0deac0bf..1f1b793984fe 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -335,8 +335,10 @@ config CGROUP_NET_CLASSID
being used in cls_cgroup and for netfilter matching.
config NET_RX_BUSY_POLL
- bool
+ bool "Low latency busy poll timeout"
default y if !PREEMPT_RT || (PREEMPT_RT && !NETCONSOLE)
+ help
+ Approximate time in us to spin waiting for packets on the device queue.
config BQL
bool
--
2.37.3
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