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Message-ID: <ed8b0bbd-e2db-e899-d3e8-8a6e98072a57@kernel.org>
Date: Fri, 15 Sep 2023 21:17:24 -0600
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Subject: Re: [PATCH v1 net-next 5/5] tcp: reorganize tcp_sock fast path
 variables
Content-Language: en-US
To: Coco Li <lixiaoyan@google.com>, Jakub Kicinski <kuba@kernel.org>,
 Eric Dumazet <edumazet@google.com>, Neal Cardwell <ncardwell@google.com>,
 Mubashir Adnan Qureshi <mubashirq@google.com>,
 Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, Chao Wu <wwchao@google.com>,
 Wei Wang <weiwan@google.com>
References: <20230916010625.2771731-1-lixiaoyan@google.com>
 <20230916010625.2771731-6-lixiaoyan@google.com>
From: David Ahern <dsahern@kernel.org>
In-Reply-To: <20230916010625.2771731-6-lixiaoyan@google.com>
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On 9/15/23 7:06 PM, Coco Li wrote:
> The variables are organized according to the following way:
> 
> - TX read-mostly hotpath cache lines
> - TXRX read-mostly hotpath cache lines
> - RX read-mostly hotpath cache lines
> - TX read-write hotpath cache line
> - TXRX read-write hotpath cache line
> - RX read-write hotpath cache line
> 
> Fastpath cachelines end after rcvq_space.
> 
> Cache line boundaries are enfored only between read-mostly and
> read-write. That is, if read-mostly tx cachelines bleed into 
> read-mostly txrx cachelines, we do not care. We care about the
> boundaries between read and write cachelines because we want
> to prevent false sharing.
> 
> Fast path variables span cache lines before change: 12
> Fast path variables span cache lines after change: 8
> 
> Tested:
> Built and installed.
> 
> Signed-off-by: Coco Li <lixiaoyan@google.com>
> Suggested-by: Eric Dumazet <edumazet@google.com>
> Reviewed-by: Wei Wang <weiwan@google.com>
> ---
>  include/linux/tcp.h | 233 ++++++++++++++++++++++----------------------
>  1 file changed, 119 insertions(+), 114 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>