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From: Eric Dumazet <edumazet@google.com>
To: Ben Greear <greearb@candelatech.com>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: net: tso: add UDP segmentation support: adds regression for ax200 upload
Date: Thu, 17 Dec 2020 11:11:37 +0100	[thread overview]
Message-ID: <CANn89iKpa1y2SKJuR9kRi=AZs94sj+-tzRs+2D0vmxh+ahEcGA@mail.gmail.com> (raw)
In-Reply-To: <765f370d-ce2d-b75a-2dde-87f69ae7c185@candelatech.com>

On Thu, Dec 17, 2020 at 12:59 AM Ben Greear <greearb@candelatech.com> wrote:
>
> On 12/16/20 3:09 PM, Ben Greear wrote:
> > Hello Eric,
> >
> > The patch below evidently causes TCP throughput to be about 50Mbps instead of 700Mbps
> > when using ax200 to upload tcp traffic.
> >
> > When I disable TSO, performance goes back up to around 700Mbps.
>
> As a followup, when I revert the patch, upload speed goes to ~900Mbps,
> so even better than just disabling TSO (I left TSO enabled after reverting the patch).
>
> Thanks,
> Ben
>

Thanks for the report !

It seems drivers/net/wireless/intel/iwlwifi/pcie/tx.c:iwl_fill_data_tbs_amsdu()
calls tso_build_hdr() with extra bytes (SNAP header),
it is not yet clear to me what is broken :/

Can you confirm which driver is used for ax200 ?

I see tso_build_hdr() also being used from
drivers/net/wireless/intel/iwlwifi/queue/tx.c

  reply	other threads:[~2020-12-17 10:12 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-16 23:09 net: tso: add UDP segmentation support: adds regression for ax200 upload Ben Greear
2020-12-16 23:59 ` Ben Greear
2020-12-17 10:11   ` Eric Dumazet [this message]
2020-12-17 17:56     ` Ben Greear
2020-12-17 18:07       ` Eric Dumazet
2020-12-17 18:13         ` Ben Greear
2020-12-17 18:20           ` Eric Dumazet
2020-12-17 20:40             ` Ben Greear
2020-12-18 20:16               ` Jakub Kicinski
2020-12-19 15:18                 ` Johannes Berg
2020-12-19 16:55                   ` Ben Greear
2020-12-21 18:46                     ` Eric Dumazet
2020-12-21 18:54                       ` Jakub Kicinski
2020-12-21 19:04                       ` Eric Dumazet
2020-12-21 19:14                         ` Eric Dumazet
2020-12-21 20:01                           ` Rainer Suhm
2020-12-24 17:48                             ` Ben Greear
2021-01-19  8:53                           ` Johannes Berg
2021-01-19 10:02                             ` Eric Dumazet
2021-01-25 14:57                               ` Johannes Berg
2021-01-25 14:58                                 ` Eric Dumazet

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