| Message ID | 20240206091909.3191-7-paul.barker.ct@bp.renesas.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Improve GbEth performance on Renesas RZ/G2L and related SoCs | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/apply | fail | Patch does not apply to net-next |
On 2/6/24 12:19 PM, Paul Barker wrote: > Software IRQ Coalescing is required to improve network stack performance > in the RZ/G2L SoC family and the RZ/G3S SoC, i.e. the SoCs which use the > GbEth IP. > > For the RZ/G2L, network throughput is comparable before and after this > change. CPU usage during TCP RX testing dropped by 6.5% and during UDP > RX testing dropped by 10%. > > For the RZ/G2UL, network throughput is greatly increased by this change > (results obtained with iperf3): > * TCP TX: 2.9% more throughput > * TCP RX: 1.1% more throughput > * UDP TX: similar throughput > * UDP RX: 41500% more throughput Wow! 8-) > For the RZ/G3S we see improvements in network throughput similar to the > RZ/G2UL. > > The improvement of UDP RX bandwidth for the single core SoCs (RZ/G2UL & > RZ/G3S) is particularly critical. > > Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com> [...] > diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h > index 55a7a08aabef..ca7a66759e35 100644 > --- a/drivers/net/ethernet/renesas/ravb.h > +++ b/drivers/net/ethernet/renesas/ravb.h > @@ -1078,6 +1078,7 @@ struct ravb_hw_info { > unsigned nc_queues:1; /* AVB-DMAC has RX and TX NC queues */ > unsigned magic_pkt:1; /* E-MAC supports magic packet detection */ > unsigned half_duplex:1; /* E-MAC supports half duplex mode */ > + unsigned needs_irq_coalesce:1; /* Requires SW IRQ Coalescing to achieve best performance */ Is this really a hardware feature? Also, s/Requires SW/Needs software/ and s/to achieve best performance//, please... [...] MBR, Sergey
On 10/02/2024 18:42, Sergey Shtylyov wrote: > On 2/6/24 12:19 PM, Paul Barker wrote: >> diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h >> index 55a7a08aabef..ca7a66759e35 100644 >> --- a/drivers/net/ethernet/renesas/ravb.h >> +++ b/drivers/net/ethernet/renesas/ravb.h >> @@ -1078,6 +1078,7 @@ struct ravb_hw_info { >> unsigned nc_queues:1; /* AVB-DMAC has RX and TX NC queues */ >> unsigned magic_pkt:1; /* E-MAC supports magic packet detection */ >> unsigned half_duplex:1; /* E-MAC supports half duplex mode */ >> + unsigned needs_irq_coalesce:1; /* Requires SW IRQ Coalescing to achieve best performance */ > > Is this really a hardware feature? It's more like a requirement to get the best out of this hardware and the Linux networking stack. I considered checking the compatible string in the probe function but I decided that storing a configuration bit in the HW info struct was cleaner. > Also, s/Requires SW/Needs software/ and s/to achieve best performance//, > please... Will do. > > [...] > > MBR, Sergey Thanks for the review, Paul
On 2/12/24 2:45 PM, Paul Barker wrote: [...] >>> diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h >>> index 55a7a08aabef..ca7a66759e35 100644 >>> --- a/drivers/net/ethernet/renesas/ravb.h >>> +++ b/drivers/net/ethernet/renesas/ravb.h >>> @@ -1078,6 +1078,7 @@ struct ravb_hw_info { >>> unsigned nc_queues:1; /* AVB-DMAC has RX and TX NC queues */ >>> unsigned magic_pkt:1; /* E-MAC supports magic packet detection */ >>> unsigned half_duplex:1; /* E-MAC supports half duplex mode */ >>> + unsigned needs_irq_coalesce:1; /* Requires SW IRQ Coalescing to achieve best performance */ >> >> Is this really a hardware feature? > > It's more like a requirement to get the best out of this hardware and the Linux networking stack. > > I considered checking the compatible string in the probe function but I decided that storing a configuration bit in the HW info struct was cleaner. Yes, but you added the new bit under the "hardware features" commet. :-) >> Also, s/Requires SW/Needs software/ and s/to achieve best performance//, >> please... > > Will do. The comment is too long, I think. :-) [...] > Thanks for the review, > Paul MBR, Sergey
On 12/02/2024 20:40, Sergey Shtylyov wrote: > On 2/12/24 2:45 PM, Paul Barker wrote: > [...] >>>> diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h >>>> index 55a7a08aabef..ca7a66759e35 100644 >>>> --- a/drivers/net/ethernet/renesas/ravb.h >>>> +++ b/drivers/net/ethernet/renesas/ravb.h >>>> @@ -1078,6 +1078,7 @@ struct ravb_hw_info { >>>> unsigned nc_queues:1; /* AVB-DMAC has RX and TX NC queues */ >>>> unsigned magic_pkt:1; /* E-MAC supports magic packet detection */ >>>> unsigned half_duplex:1; /* E-MAC supports half duplex mode */ >>>> + unsigned needs_irq_coalesce:1; /* Requires SW IRQ Coalescing to achieve best performance */ >>> >>> Is this really a hardware feature? >> >> It's more like a requirement to get the best out of this hardware and the Linux networking stack. >> >> I considered checking the compatible string in the probe function but I decided that storing a configuration bit in the HW info struct was cleaner. > > Yes, but you added the new bit under the "hardware features" commet. :-) > >>> Also, s/Requires SW/Needs software/ and s/to achieve best performance//, >>> please... >> >> Will do. > > The comment is too long, I think. :-) I'll fix both in the next revision.
diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h index 55a7a08aabef..ca7a66759e35 100644 --- a/drivers/net/ethernet/renesas/ravb.h +++ b/drivers/net/ethernet/renesas/ravb.h @@ -1078,6 +1078,7 @@ struct ravb_hw_info { unsigned nc_queues:1; /* AVB-DMAC has RX and TX NC queues */ unsigned magic_pkt:1; /* E-MAC supports magic packet detection */ unsigned half_duplex:1; /* E-MAC supports half duplex mode */ + unsigned needs_irq_coalesce:1; /* Requires SW IRQ Coalescing to achieve best performance */ }; struct ravb_private { diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index 661fd86899ac..7bb80608f260 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -2639,6 +2639,7 @@ static const struct ravb_hw_info gbeth_hw_info = { .tx_counters = 1, .carrier_counters = 1, .half_duplex = 1, + .needs_irq_coalesce = 1, }; static const struct of_device_id ravb_match_table[] = { @@ -2983,6 +2984,9 @@ static int ravb_probe(struct platform_device *pdev) if (info->nc_queues) netif_napi_add(ndev, &priv->napi[RAVB_NC], ravb_poll); + if (info->needs_irq_coalesce) + netdev_sw_irq_coalesce_default_on(ndev); + /* Network device register */ error = register_netdev(ndev); if (error)
Software IRQ Coalescing is required to improve network stack performance in the RZ/G2L SoC family and the RZ/G3S SoC, i.e. the SoCs which use the GbEth IP. For the RZ/G2L, network throughput is comparable before and after this change. CPU usage during TCP RX testing dropped by 6.5% and during UDP RX testing dropped by 10%. For the RZ/G2UL, network throughput is greatly increased by this change (results obtained with iperf3): * TCP TX: 2.9% more throughput * TCP RX: 1.1% more throughput * UDP TX: similar throughput * UDP RX: 41500% more throughput For the RZ/G3S we see improvements in network throughput similar to the RZ/G2UL. The improvement of UDP RX bandwidth for the single core SoCs (RZ/G2UL & RZ/G3S) is particularly critical. Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com> --- drivers/net/ethernet/renesas/ravb.h | 1 + drivers/net/ethernet/renesas/ravb_main.c | 4 ++++ 2 files changed, 5 insertions(+)