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SubjectRe: [PATCH v8 RESEND 6/6] r8169: Disable ASPM while doing NAPI poll
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On 21.02.2023 03:38, Kai-Heng Feng wrote:
> NAPI poll of Realtek NICs don't seem to perform well ASPM is enabled.
> The vendor driver uses a mechanism called "dynamic ASPM" to toggle ASPM
> based on the packet number in given time period.
>
> Instead of implementing "dynamic ASPM", use a more straightforward way
> by disabling ASPM during NAPI poll, as a similar approach was
> implemented to solve slow performance on Realtek wireless NIC, see
> commit 24f5e38a13b5 ("rtw88: Disable PCIe ASPM while doing NAPI poll on
> 8821CE").
>
> Since NAPI poll should be handled as fast as possible, also remove the
> delay in rtl_hw_aspm_clkreq_enable() which was added by commit
> 94235460f9ea ("r8169: Align ASPM/CLKREQ setting function with vendor
> driver").
>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> v8:
> - New patch.
>
> drivers/net/ethernet/realtek/r8169_main.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
> index 897f90b48bba6..4d4a802346ae3 100644
> --- a/drivers/net/ethernet/realtek/r8169_main.c
> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> @@ -2711,8 +2711,6 @@ static void rtl_hw_aspm_clkreq_enable(struct rtl8169_private *tp, bool enable)
> RTL_W8(tp, Config2, RTL_R8(tp, Config2) & ~ClkReqEn);
> RTL_W8(tp, Config5, RTL_R8(tp, Config5) & ~ASPM_en);
> }
> -
> - udelay(10);
> }
>
> static void rtl_set_fifo_size(struct rtl8169_private *tp, u16 rx_stat,
> @@ -4577,6 +4575,12 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)
> struct net_device *dev = tp->dev;
> int work_done;
>
> + if (tp->aspm_manageable) {
> + rtl_unlock_config_regs(tp);

NAPI poll runs in softirq context (except for threaded NAPI).
Therefore you should use a spinlock instead of a mutex.

> + rtl_hw_aspm_clkreq_enable(tp, false);
> + rtl_lock_config_regs(tp);
> + }
> +
> rtl_tx(dev, tp, budget);
>
> work_done = rtl_rx(dev, tp, budget);
> @@ -4584,6 +4588,12 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)
> if (work_done < budget && napi_complete_done(napi, work_done))
> rtl_irq_enable(tp);
>
> + if (tp->aspm_manageable) {
> + rtl_unlock_config_regs(tp);
> + rtl_hw_aspm_clkreq_enable(tp, true);
> + rtl_lock_config_regs(tp);

Why not moving lock/unlock into rtl_hw_aspm_clkreq_enable()?

> + }
> +
> return work_done;
> }
>

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