netdev - [Linux-kernel-mentees][PATCH 0/2] reorder members of structures in virtio

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Date:   Wed, 30 Sep 2020 10:47:20 +0530
From:   Anant Thazhemadam <anant.thazhemadam@...il.com>
To:     mst@...hat.com, jasowang@...hat.com, davem@...emloft.net,
        kuba@...nel.org, ast@...nel.org, daniel@...earbox.net,
        hawk@...nel.org, john.fastabend@...il.com
Cc:     Anant Thazhemadam <anant.thazhemadam@...il.com>,
        linux-kernel-mentees@...ts.linuxfoundation.org,
        virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, bpf@...r.kernel.org
Subject: [Linux-kernel-mentees][PATCH 0/2] reorder members of structures in virtio_net for optimization

The structures virtnet_info and receive_queue have byte holes in 
middle, and their members could do with some rearranging 
(order-of-declaration wise) in order to overcome this.

Rearranging the members helps in:
  * elimination the byte holes in the middle of the structures
  * reduce the size of the structure (virtnet_info)
  * have more members stored in one cache line (as opposed to 
    unnecessarily crossing the cacheline boundary and spanning
    different cachelines)

The analysis was performed using pahole.

These patches may be applied in any order.

Anant Thazhemadam (2):
  net: reorder members of virtnet_info for optimization
  net: reorder members of receive_queue in virtio_net for optimization

 drivers/net/virtio_net.c | 44 +++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 21 deletions(-)

-- 
2.25.1