Re: [REGRESSION] bisected: iwlwifi: use already mapped data when TXing an AMSDU

[Kalle Valo <kvalo@kernel.org>]

"Berg, Benjamin" <benjamin.berg@intel.com> writes:

> Hi,
>
> On Wed, 2024-08-07 at 16:49 +0300, Kalle Valo wrote:
>> Chris Bainbridge <chris.bainbridge@gmail.com> writes:
>> 
>> > On Wed, 7 Aug 2024 at 13:10, Kalle Valo <kvalo@kernel.org> wrote:
>> > > [SNIP]
>> > Not really. It is functional but tx throughput is severely
>> > degraded,
>> > iperf shows ~1mbit/sec instead of the usual ~600mbit. Rx throughput
>> > (measured with `iperf -c ... -R`) doesn't seem to be affected.
>> 
>> Ok, so a quite severe issue. Hopefully Intel can find a fix,
>> otherwise
>> we need to consider should we revert commit 90db50755228 ("wifi:
>> iwlwifi: use already mapped data when TXing an AMSDU") for v6.11.
>
> Yes, if we do not have a fix soon we'll need to revert. If so, then we
> should also revert:
>
> wifi: iwlwifi: keep the TSO and workaround pages mapped
> wifi: iwlwifi: map entire SKB when sending AMSDUs
>
> as well as the related bugfix:
> wifi: iwlwifi: correctly reference TSO page information
>
> Otherwise there is a performance impact as DMA mapping is effectively
> done twice.

That's good to know, thanks. But let's hope you find a fix.

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