Re: [PATCH v1 net-next 2/2] tcp: reorganize tcp_sock fast path variables

[David Ahern <dsahern@kernel.org>]

On 12/4/23 1:12 PM, Coco Li wrote:
> The variables are organized according in 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 enforced 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
> 
> Suggested-by: Eric Dumazet <edumazet@google.com>
> Reviewed-by: Wei Wang <weiwan@google.com>
> Signed-off-by: Coco Li <lixiaoyan@google.com>
> ---
>  include/linux/tcp.h | 248 ++++++++++++++++++++++++--------------------
>  net/ipv4/tcp.c      |  93 +++++++++++++++++
>  2 files changed, 227 insertions(+), 114 deletions(-)
> 

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