[PATCH net-next 0/7] net: stmmac: CPU Performance Improvements

From: Jose Abreu
Date: Wed Nov 13 2019 - 10:12:43 EST


CPU Performance improvements for stmmac. Please check bellow for results
before and after the series.

Patch 1/7, allows RX Interrupt on Completion to be disabled and only use the
RX HW Watchdog.

Patch 2/7, setups the default RX coalesce settings instead of using the
minimum value.

Patch 3/7, enables the Transmit Buffer Unavailable interrupt on GMAC4+ cores
so that we don't miss any packet that could have been coalesced.

Patch 4/7 and 5/7, removes the uneeded computations for RX Flow Control
activation/de-activation, on some cases.

Patch 6/7, tunes-up the default coalesce settings.

Patch 7/7, corrects the interpretation of TX Coalesce.


NetPerf UDP Results:
--------------------

Socket Message Elapsed Messages CPU Service
Size Size Time Okay Errors Throughput Util Demand
bytes bytes secs # # 10^6bits/sec % SS us/KB
--- XGMAC@xxxx: Before
212992 1400 10.00 2100620 0 2351.7 36.69 5.112
212992 10.00 2100539 2351.6 26.18 3.648
--- XGMAC@xxxx: After
212992 1400 10.00 2116860 0 2370.4 27.61 3.816
212992 10.00 2111552 2364.5 17.41 2.407

--- GMAC5@1G: Before
212992 1400 10.00 786000 0 880.2 34.71 12.923
212992 10.00 786000 880.2 23.42 8.719
--- GMAC5@1G: After
212992 1400 10.00 847702 0 949.3 15.07 5.201
212992 10.00 847702 949.3 12.91 4.456


Perf TCP Results on RX Path:
----------------------------
--- XGMAC@xxxx: Before
22.51% swapper [stmmac] [k] dwxgmac2_dma_interrupt
10.82% swapper [stmmac] [k] dwxgmac2_host_mtl_irq_status
5.21% swapper [stmmac] [k] dwxgmac2_host_irq_status
4.67% swapper [stmmac] [k] dwxgmac3_safety_feat_irq_status
3.63% swapper [kernel.kallsyms] [k] stack_trace_consume_entry
2.74% iperf3 [kernel.kallsyms] [k] copy_user_enhanced_fast_string
2.52% swapper [kernel.kallsyms] [k] update_stack_state
1.94% ksoftirqd/0 [stmmac] [k] dwxgmac2_dma_interrupt
1.45% iperf3 [kernel.kallsyms] [k] queued_spin_lock_slowpath
1.26% swapper [kernel.kallsyms] [k] create_object
--- XGMAC@xxxx: After
12.00% swapper [stmmac] [k] dwxgmac2_dma_interrupt
5.96% swapper [kernel.kallsyms] [k] stack_trace_consume_entry
5.65% swapper [stmmac] [k] dwxgmac2_host_mtl_irq_status
4.36% swapper [kernel.kallsyms] [k] update_stack_state
3.91% iperf3 [kernel.kallsyms] [k] copy_user_enhanced_fast_string
2.82% swapper [stmmac] [k] dwxgmac2_host_irq_status
2.62% swapper [stmmac] [k] dwxgmac3_safety_feat_irq_status
2.25% swapper [kernel.kallsyms] [k] create_object
2.03% swapper [stmmac] [k] stmmac_napi_poll_rx
1.97% swapper [kernel.kallsyms] [k] unwind_next_frame.part.4

--- GMAC5@1G: Before
31.29% swapper [stmmac] [k] dwmac4_dma_interrupt
14.57% swapper [stmmac] [k] dwmac4_irq_mtl_status
10.66% swapper [stmmac] [k] dwmac4_irq_status
1.97% swapper [kernel.kallsyms] [k] stack_trace_consume_entry
1.73% iperf3 [kernel.kallsyms] [k] copy_user_enhanced_fast_string
1.59% swapper [kernel.kallsyms] [k] update_stack_state
1.15% iperf3 [kernel.kallsyms] [k] do_syscall_64
1.01% ksoftirqd/0 [stmmac] [k] dwmac4_dma_interrupt
0.89% swapper [kernel.kallsyms] [k] __default_send_IPI_dest_field
0.75% swapper [stmmac] [k] stmmac_napi_poll_rx
--- GMAC5@1G: After
9.27% swapper [stmmac] [k] dwmac4_dma_interrupt
6.35% swapper [kernel.kallsyms] [k] stack_trace_consume_entry
4.94% swapper [kernel.kallsyms] [k] update_stack_state
4.70% swapper [stmmac] [k] dwmac4_irq_mtl_status
3.58% swapper [stmmac] [k] dwmac4_irq_status
3.42% iperf3 [kernel.kallsyms] [k] copy_user_enhanced_fast_string
2.18% swapper [kernel.kallsyms] [k] unwind_next_frame.part.4
2.17% swapper [stmmac] [k] stmmac_napi_poll_rx
2.15% swapper [kernel.kallsyms] [k] create_object
1.26% swapper [kernel.kallsyms] [k] unwind_get_return_address

---
Cc: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxx>
Cc: Jose Abreu <joabreu@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---

Jose Abreu (7):
net: stmmac: Do not set RX IC bit if RX Coalesce is zero
net: stmmac: Setup a default RX Coalesce value instead of the minimum
net: stmmac: gmac4+: Enable the TBU Interrupt
net: stmmac: gmac4+: Remove uneeded computation for RFA/RFD
net: stmmac: xgmac: Remove uneeded computation for RFA/RFD
net: stmmac: Tune-up default coalesce settings
net: stmmac: TX Coalesce should be per-packet

drivers/net/ethernet/stmicro/stmmac/common.h | 5 +++--
drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c | 14 ++------------
drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h | 2 ++
drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c | 14 ++------------
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 14 ++++++++------
5 files changed, 17 insertions(+), 32 deletions(-)

--
2.7.4