Messages in this thread | | | From | Kai-Heng Feng <> | Date | Mon, 9 Aug 2021 19:18:33 +0800 | Subject | Re: [PATCH 1/2] r8169: Implement dynamic ASPM mechanism |
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On Sat, Aug 7, 2021 at 2:47 AM Heiner Kallweit <hkallweit1@gmail.com> wrote: > > On 03.08.2021 17:28, Kai-Heng Feng wrote: > > r8169 NICs on some platforms have abysmal speed when ASPM is enabled. > > Same issue can be observed with older vendor drivers. > > > > The issue is however solved by the latest vendor driver. There's a new > > mechanism, which disables r8169's internal ASPM when the NIC has > > substantial network traffic, and vice versa. > > > > So implement the same mechanism here to resolve the issue. > > > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > > --- > > drivers/net/ethernet/realtek/r8169_main.c | 36 +++++++++++++++++++++++ > > 1 file changed, 36 insertions(+) > > > > diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c > > index c7af5bc3b8af..e257d3cd885e 100644 > > --- a/drivers/net/ethernet/realtek/r8169_main.c > > +++ b/drivers/net/ethernet/realtek/r8169_main.c > > @@ -624,6 +624,10 @@ struct rtl8169_private { > > > > unsigned supports_gmii:1; > > unsigned aspm_manageable:1; > > + unsigned aspm_enabled:1; > > + struct timer_list aspm_timer; > > + u32 aspm_packet_count; > > + > > dma_addr_t counters_phys_addr; > > struct rtl8169_counters *counters; > > struct rtl8169_tc_offsets tc_offset; > > @@ -2671,6 +2675,8 @@ static void rtl_hw_aspm_clkreq_enable(struct rtl8169_private *tp, bool enable) > > RTL_W8(tp, Config5, RTL_R8(tp, Config5) & ~ASPM_en); > > } > > > > + tp->aspm_enabled = enable; > > + > > udelay(10); > > } > > > > @@ -4408,6 +4414,7 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp, > > > > dirty_tx = tp->dirty_tx; > > > > + tp->aspm_packet_count += tp->cur_tx - dirty_tx; > > while (READ_ONCE(tp->cur_tx) != dirty_tx) { > > unsigned int entry = dirty_tx % NUM_TX_DESC; > > u32 status; > > @@ -4552,6 +4559,8 @@ static int rtl_rx(struct net_device *dev, struct rtl8169_private *tp, int budget > > rtl8169_mark_to_asic(desc); > > } > > > > + tp->aspm_packet_count += count; > > + > > return count; > > } > > > > @@ -4659,8 +4668,31 @@ static int r8169_phy_connect(struct rtl8169_private *tp) > > return 0; > > } > > > > +#define ASPM_PACKET_THRESHOLD 10 > > +#define ASPM_TIMER_INTERVAL 1000 > > + > > +static void rtl8169_aspm_timer(struct timer_list *timer) > > +{ > > + struct rtl8169_private *tp = from_timer(tp, timer, aspm_timer); > > + bool enable; > > + > > + enable = tp->aspm_packet_count <= ASPM_PACKET_THRESHOLD; > > + > > + if (tp->aspm_enabled != enable) { > > + rtl_unlock_config_regs(tp); > > + rtl_hw_aspm_clkreq_enable(tp, enable); > > + rtl_lock_config_regs(tp); > > + } > > + > > + tp->aspm_packet_count = 0; > > + > > + mod_timer(timer, jiffies + msecs_to_jiffies(ASPM_TIMER_INTERVAL)); > > +} > > + > > static void rtl8169_down(struct rtl8169_private *tp) > > { > > + del_timer_sync(&tp->aspm_timer); > > + > > /* Clear all task flags */ > > bitmap_zero(tp->wk.flags, RTL_FLAG_MAX); > > > > @@ -4687,6 +4719,10 @@ static void rtl8169_up(struct rtl8169_private *tp) > > rtl_reset_work(tp); > > > > phy_start(tp->phydev); > > + > > + timer_setup(&tp->aspm_timer, rtl8169_aspm_timer, 0); > > + mod_timer(&tp->aspm_timer, > > + jiffies + msecs_to_jiffies(ASPM_TIMER_INTERVAL)); > > } > > > > static int rtl8169_close(struct net_device *dev) > > > > I have one more question / concern regarding this workaround: > If bigger traffic starts and results in a congestion (let's call it like that > because we don't know in detail what happens in the chip), then it may take > up to a second until ASPM gets disabled and traffic gets back to normal. > This second is good enough to prevent that the timeout watchdog fires. > However in this second supposedly traffic is very limited, if possible at all. > Means if we have a network traffic pattern with alternating quiet and busy > periods then we may see a significant impact on performance. > Is this something that you tested?
No, we didn't test this scenario. Realtek told us that dynamic ASPM is also used by Windows driver, but I don't know the interval used by Windows driver. For now I think it's better to stick with vendor defined value.
Kai-Heng
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