From: Jakub Kicinski <kuba@kernel.org>
To: edumazet@google.com
Cc: kuniyu@google.com, ncardwell@google.com, netdev@vger.kernel.org,
davem@davemloft.net, pabeni@redhat.com, andrew+netdev@lunn.ch,
horms@kernel.org
Subject: Re: [PATCH net-next] tcp: try to defer / return acked skbs to originating CPU
Date: Sat, 17 Jan 2026 09:10:10 -0800 [thread overview]
Message-ID: <20260117091010.3133de3b@kernel.org> (raw)
In-Reply-To: <20260117164255.785751-1-kuba@kernel.org>
On Sat, 17 Jan 2026 08:42:55 -0800 Jakub Kicinski wrote:
> Running a memcache-like workload under production(ish) load
> on a 300 thread AMD machine we see ~3% of CPU time spent
> in kmem_cache_free() via tcp_ack(), freeing skbs from rtx queue.
> This workloads pins workers away from softirq CPU so
> the Tx skbs are pretty much always allocated on a different
> CPU than where the ACKs arrive. Try to use the defer skb free
> queue to return the skbs back to where they came from.
> This results in a ~4% performance improvement for the workload.
In the interest of full transparency the performance testing was
done on a 6.13-ish kernel. But I don't see anything that'd make
the situation better upstream..
next prev parent reply other threads:[~2026-01-17 17:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-17 16:42 [PATCH net-next] tcp: try to defer / return acked skbs to originating CPU Jakub Kicinski
2026-01-17 17:10 ` Jakub Kicinski [this message]
2026-01-17 18:16 ` Eric Dumazet
2026-01-17 23:03 ` Jakub Kicinski
2026-01-18 12:15 ` Eric Dumazet
2026-01-19 17:04 ` Jakub Kicinski
2026-01-29 23:04 ` Jakub Kicinski
2026-01-29 23:10 ` Jakub Kicinski
2026-02-16 16:06 ` Eric Dumazet
2026-02-16 17:49 ` Jakub Kicinski
2026-02-16 17:58 ` Eric Dumazet
2026-02-16 18:11 ` Jakub Kicinski
2026-02-16 18:16 ` Eric Dumazet
2026-02-17 21:50 ` Jakub Kicinski
2026-02-17 21:56 ` Eric Dumazet
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