[Linux-stm32] [PATCH net-next 0/7] net: stmmac: CPU Performance Improvements

[Jose Abreu]

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 at 2.5G: Before
212992    1400   10.00     2100620      0     2351.7     36.69    5.112
212992           10.00     2100539            2351.6     26.18    3.648
--- XGMAC at 2.5G: After
212992    1400   10.00     2116860      0     2370.4     27.61    3.816 
212992           10.00     2111552            2364.5     17.41    2.407

--- GMAC5 at 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 at 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 at 2.5G: 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 at 2.5G: 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 at 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 at 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 at st.com>
Cc: Alexandre Torgue <alexandre.torgue at st.com>
Cc: Jose Abreu <joabreu at synopsys.com>
Cc: "David S. Miller" <davem at davemloft.net>
Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
Cc: netdev at vger.kernel.org
Cc: linux-stm32 at st-md-mailman.stormreply.com
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---

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