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Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX

From Corentin Labbe <clabbe.montjoie@gmail.com>
Newsgroups linux.kernel
Subject Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX
Date 2017-02-03 14:50 +0100
Message-ID <t6Mps-2cV-29@gated-at.bofh.it> (permalink)
References <t5CLw-7mj-19@gated-at.bofh.it> <t5CLw-7mj-21@gated-at.bofh.it> <t5UyJ-17o-1@gated-at.bofh.it>
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On Tue, Jan 31, 2017 at 11:12:25PM -0500, David Miller wrote:
> From: Corentin Labbe <clabbe.montjoie@gmail.com>
> Date: Tue, 31 Jan 2017 10:11:48 +0100
> 
> > The stmmac driver run TX completion under NAPI but without checking
> > the work done by the TX completion function.
> 
> The current behavior is correct and completely intentional.
> 
> A driver should _never_ account TX work to the NAPI poll budget.
> 
> This is because TX liberation is orders of magnitude cheaper than
> receiving a packet, and such SKB freeing makes more SKBs available
> for RX processing.
> 
> Therefore, TX work should never count against the NAPI budget.
> 
> Please do not fix something which is not broken.

So at least the documentation I read must be fixed (https://wiki.linuxfoundation.org/networking/napi)

So perhaps the best way is to do like intel igb/ixgbe, keeping under NAPI until the stmmac_tx_clean function said that it finish handling the queue ?

Regards
Corentin Labbe

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Thread

[PATCH 13/17] net: stmmac: Implement NAPI for TX Corentin Labbe <clabbe.montjoie@gmail.com> - 2017-01-31 10:20 +0100
  Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX Giuseppe CAVALLARO <peppe.cavallaro@st.com> - 2017-01-31 11:30 +0100
    Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX Corentin Labbe <clabbe.montjoie@gmail.com> - 2017-01-31 14:50 +0100
  Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX David Miller <davem@davemloft.net> - 2017-02-01 05:20 +0100
    Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX Corentin Labbe <clabbe.montjoie@gmail.com> - 2017-02-03 14:50 +0100
      Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX David Miller <davem@davemloft.net> - 2017-02-03 16:20 +0100
        Re: [PATCH 13/17] net: stmmac: Implement NAPI for TX Corentin Labbe <clabbe.montjoie@gmail.com> - 2017-02-03 17:00 +0100

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