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In-Reply-To: <56d4941a-ad35-37ca-48ca-5f1bf7a86d25@quicinc.com>
From:   Abhishek Kumar <kuabhs@chromium.org>
Date:   Wed, 28 Dec 2022 16:01:38 -0800
Message-ID: <CACTWRwt7oQrCyHf=ZF6dW8TtRhOfa14XMZW39cYZWi4hhszcqg@mail.gmail.com>
Subject: Re: [PATCH] ath10k: snoc: enable threaded napi on WCN3990
To:     Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
Cc:     kvalo@kernel.org, ath10k@lists.infradead.org,
        linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
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Precedence: bulk

Apologies for the late reply. Please see my response inline.

On Tue, Dec 20, 2022 at 4:14 AM Manikanta Pubbisetty
<quic_mpubbise@quicinc.com> wrote:
>
> On 12/20/2022 1:25 PM, Abhishek Kumar wrote:
> > NAPI poll can be done in threaded context along with soft irq
> > context. Threaded context can be scheduled efficiently, thus
> > creating less of bottleneck during Rx processing. This patch is
> > to enable threaded NAPI on ath10k driver.
> >
> > Based on testing, it was observed that on WCN3990, the CPU0 reaches
> > 100% utilization when napi runs in softirq context. At the same
> > time the other CPUs are at low consumption percentage. This
> > does not allow device to reach its maximum throughput potential.
> > After enabling threaded napi, CPU load is balanced across all CPUs
> > and following improvments were observed:
> > - UDP_RX increase by ~22-25%
> > - TCP_RX increase by ~15%
> >
> > Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.3.2.2-00696-QCAHLSWMTPL-1
> > Signed-off-by: Abhishek Kumar <kuabhs@chromium.org>
> > ---
> >
> >   drivers/net/wireless/ath/ath10k/core.c | 16 ++++++++++++++++
> >   drivers/net/wireless/ath/ath10k/hw.h   |  2 ++
> >   drivers/net/wireless/ath/ath10k/snoc.c |  3 +++
> >   3 files changed, 21 insertions(+)
> >
> > diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> > index 5eb131ab916fd..ee4b6ba508c81 100644
> > --- a/drivers/net/wireless/ath/ath10k/core.c
> > +++ b/drivers/net/wireless/ath/ath10k/core.c
> > @@ -100,6 +100,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA988X_HW_2_0_VERSION,
> > @@ -140,6 +141,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA9887_HW_1_0_VERSION,
> > @@ -181,6 +183,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA6174_HW_3_2_VERSION,
> > @@ -217,6 +220,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA6174_HW_2_1_VERSION,
> > @@ -257,6 +261,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA6174_HW_2_1_VERSION,
> > @@ -297,6 +302,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA6174_HW_3_0_VERSION,
> > @@ -337,6 +343,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA6174_HW_3_2_VERSION,
> > @@ -381,6 +388,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA99X0_HW_2_0_DEV_VERSION,
> > @@ -427,6 +435,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA9984_HW_1_0_DEV_VERSION,
> > @@ -480,6 +489,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA9888_HW_2_0_DEV_VERSION,
> > @@ -530,6 +540,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA9377_HW_1_0_DEV_VERSION,
> > @@ -570,6 +581,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA9377_HW_1_1_DEV_VERSION,
> > @@ -612,6 +624,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA9377_HW_1_1_DEV_VERSION,
> > @@ -645,6 +658,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = QCA4019_HW_1_0_DEV_VERSION,
> > @@ -692,6 +706,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = false,
> >               .use_fw_tx_credits = true,
> >               .delay_unmap_buffer = false,
> > +             .enable_threaded_napi = false,
> >       },
> >       {
> >               .id = WCN3990_HW_1_0_DEV_VERSION,
> > @@ -725,6 +740,7 @@ static const struct ath10k_hw_params ath10k_hw_params_list[] = {
> >               .hw_restart_disconnect = true,
> >               .use_fw_tx_credits = false,
> >               .delay_unmap_buffer = true,
> > +             .enable_threaded_napi = true,
> >       },
> >   };
> >
> > diff --git a/drivers/net/wireless/ath/ath10k/hw.h b/drivers/net/wireless/ath/ath10k/hw.h
> > index 9643031a4427a..adf3076b96503 100644
> > --- a/drivers/net/wireless/ath/ath10k/hw.h
> > +++ b/drivers/net/wireless/ath/ath10k/hw.h
> > @@ -639,6 +639,8 @@ struct ath10k_hw_params {
> >       bool use_fw_tx_credits;
> >
> >       bool delay_unmap_buffer;
> > +
> > +     bool enable_threaded_napi;
> >   };
> >
> >   struct htt_resp;
> > diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
> > index cfcb759a87dea..b94150fb6ef06 100644
> > --- a/drivers/net/wireless/ath/ath10k/snoc.c
> > +++ b/drivers/net/wireless/ath/ath10k/snoc.c
> > @@ -927,6 +927,9 @@ static int ath10k_snoc_hif_start(struct ath10k *ar)
> >
> >       bitmap_clear(ar_snoc->pending_ce_irqs, 0, CE_COUNT_MAX);
> >
> > +     if (ar->hw_params.enable_threaded_napi)
> > +             dev_set_threaded(&ar->napi_dev, true);
> > +
>
> Since this is done in the API specific to WCN3990, we do not need
> hw_param for this.
Just so that I am clear, are you suggesting to enable this by default
in snoc.c, similar to what you did in
https://lore.kernel.org/all/20220905071805.31625-2-quic_mpubbise@quicinc.com/
. If my understanding is correct and there is no objection, I can
remove hw_param and enable it by default on snoc.c .
I used hw_param because, as I see it, threaded NAPI can have some
adverse effect on the cache utilization and power.

Thanks
Abhishek
>
> Thanks,
> Manikanta