From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Eric Dumazet <edumazet@google.com>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>,
Neil Horman <nhorman@tuxdriver.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Subject: Re: [PATCH net] af_packet: do not call packet_read_pending() from tpacket_destruct_skb()
Date: Wed, 15 May 2024 14:02:59 -0400 [thread overview]
Message-ID: <6644f8d33638a_2af87294af@willemb.c.googlers.com.notmuch> (raw)
In-Reply-To: <20240515163358.4105915-1-edumazet@google.com>
Eric Dumazet wrote:
> trafgen performance considerably sank on hosts with many cores
> after the blamed commit.
>
> packet_read_pending() is very expensive, and calling it
> in af_packet fast path defeats Daniel intent in commit
> b013840810c2 ("packet: use percpu mmap tx frame pending refcount")
>
> tpacket_destruct_skb() makes room for one packet, we can immediately
> wakeup a producer, no need to completely drain the tx ring.
>
> Fixes: 89ed5b519004 ("af_packet: Block execution of tasks waiting for transmit to complete in AF_PACKET")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Thanks!
next prev parent reply other threads:[~2024-05-15 18:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-15 16:33 [PATCH net] af_packet: do not call packet_read_pending() from tpacket_destruct_skb() Eric Dumazet
2024-05-15 18:02 ` Willem de Bruijn [this message]
2024-05-17 2:40 ` patchwork-bot+netdevbpf
2024-05-21 9:34 ` Daniel Borkmann
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