netdev - Re: [PATCH v2] net: Make skb_segment not to compute checksum if network controller supports checksumming

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Message-ID: <CABGOaVSddVL-T-Sz_GPuRoZbKM_HsZND84rJUm2G9RRw6cUwCQ@mail.gmail.com>
Date:   Thu, 5 Mar 2020 12:02:55 +0530
From:   Yadu Kishore <kyk.segfault@...il.com>
To:     David Laight <David.Laight@...lab.com>,
        Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        David Miller <davem@...emloft.net>
Cc:     Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH v2] net: Make skb_segment not to compute checksum if
 network controller supports checksumming

Hi all,

Though there is scope to optimise the checksum code (from C to asm) for such
architectures, it is not the intent of this patchset.
The intent here is only to enable offloading checksum during GSO.

The perf data I presented shows that ~7.4% of the CPU is spent doing checksum
in the GSO path for architectures where the checksum code is not implemented in
assembly (arm64).
If the network controller hardware supports checksumming, then I feel
that it is worthwhile to offload this even during GSO for such architectures
and save the 7.25% of the host cpu cycles.

Thanks,
Yadu Kishore