[PATCH v2] ath10k: snoc: enable threaded napi on WCN3990

[Abhishek Kumar]

Hi Kale,

Gentle reminder for your comments.

Thanks
Abhishek

On Thu, Feb 2, 2023 at 4:02 PM Abhishek Kumar <kuabhs at chromium.org> 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%
>
> Here are some of the additional raw data with and without threaded napi:
> ==================================================
> udp_rx(Without threaded NAPI)
> 435.98+-5.16 : Channel 44
> 439.06+-0.66 : Channel 157
>
> udp_rx(With threaded NAPI)
> 509.73+-41.03 : Channel 44
> 549.97+-7.62 : Channel 157
> ===================================================
> udp_tx(Without threaded NAPI)
> 461.31+-0.69  : Channel 44
> 461.46+-0.78 : Channel 157
>
> udp_tx(With threaded NAPI)
> 459.20+-0.77 : Channel 44
> 459.78+-1.08 : Channel 157
> ===================================================
> tcp_rx(Without threaded NAPI)
> 472.63+-2.35 : Channel 44
> 469.29+-6.31 : Channel 157
>
> tcp_rx(With threaded NAPI)
> 498.49+-2.44 : Channel 44
> 541.14+-40.65 : Channel 157
> ===================================================
> tcp_tx(Without threaded NAPI)
> 317.34+-2.37 : Channel 44
> 317.01+-2.56 : Channel 157
>
> tcp_tx(With threaded NAPI)
> 371.34+-2.36 : Channel 44
> 376.95+-9.40 : Channel 157
> ===================================================
>
> Tested-on: WCN3990 hw1.0 SNOC WLAN.HL.3.2.2-00696-QCAHLSWMTPL-1
> Signed-off-by: Abhishek Kumar <kuabhs at chromium.org>
> ---
>
> Changes in v2:
> - Removed the hw param checks to add dev_set_threaded() to snoc.c
> - Added some more test data in the commit message.
>
>  drivers/net/wireless/ath/ath10k/snoc.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
> index cfcb759a87de..0f6d2f67ff6b 100644
> --- a/drivers/net/wireless/ath/ath10k/snoc.c
> +++ b/drivers/net/wireless/ath/ath10k/snoc.c
> @@ -927,6 +927,7 @@ static int ath10k_snoc_hif_start(struct ath10k *ar)
>
>         bitmap_clear(ar_snoc->pending_ce_irqs, 0, CE_COUNT_MAX);
>
> +       dev_set_threaded(&ar->napi_dev, true);
>         ath10k_core_napi_enable(ar);
>         ath10k_snoc_irq_enable(ar);
>         ath10k_snoc_rx_post(ar);
> --
> 2.39.1.519.gcb327c4b5f-goog
>