Merge branch 'net-rps-rfs-improvements'

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Eric Dumazet says:

====================
net: rps/rfs improvements

Jason Xing attempted to optimize napi_schedule_rps() by avoiding
unneeded NET_RX_SOFTIRQ raises: [1], [2]

This is quite complex to implement properly. I chose to implement
the idea, and added a similar optimization in ____napi_schedule()

Overall, in an intensive RPC workload, with 32 TX/RX queues with RFS
I was able to observe a ~10% reduction of NET_RX_SOFTIRQ
invocations.

While this had no impact on throughput or cpu costs on this synthetic
benchmark, we know that firing NET_RX_SOFTIRQ from softirq handler
can force __do_softirq() to wakeup ksoftirqd when need_resched() is true.
This can have a latency impact on stressed hosts.

[1] https://lore.kernel.org/lkml/20230325152417.5403-1-kerneljasonxing@gmail.com/
[2] https://lore.kernel.org/netdev/20230328142112.12493-1-kerneljasonxing@gmail.com/
====================

Link: https://lore.kernel.org/r/20230328235021.1048163-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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This commit is contained in:

Paolo Abeni 2023-03-30 13:40:04 +02:00

parent 7079d5e61a 8b43fd3d1d

commit 4ddd6375c3

2 changed files with 37 additions and 10 deletions

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include/linux/netdevice.h

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46

net/core/dev.c

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