RE: [PATCH V2 net-next 0/2] net: fec: fix TX bandwidth fluctuations

Hi Andrew,

-----Original Message-----
From: Andrew Lunn <andrew@lunn.ch>
Sent: 2021年6月17日 21:04
To: Joakim Zhang <redacted>
Cc: David Miller <davem@davemloft.net>; kuba@kernel.org;
frieder.schrempf@kontron.de; netdev@vger.kernel.org;
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 net-next 0/2] net: fec: fix TX bandwidth fluctuations

On Thu, Jun 17, 2021 at 11:40:58AM +0000, Joakim Zhang wrote:

quoted

Hi Andrew,

quoted

-----Original Message-----
From: Andrew Lunn <andrew@lunn.ch>
Sent: 2021年6月16日 21:06
To: Joakim Zhang <redacted>
Cc: David Miller <davem@davemloft.net>; kuba@kernel.org;
frieder.schrempf@kontron.de; netdev@vger.kernel.org;
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 net-next 0/2] net: fec: fix TX bandwidth
fluctuations

quoted

I try below build options, also can't reproduce this issue, so
really don't know

how to fix it.

quoted

make ARCH=arm64 distclean
make ARCH=arm64 allmodconfig
make -j8 ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- W=1 / make
-j8

ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- W=2 / make -j8
ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- W=3

quoted

I saw many unrelated warnings...

Then it could be sparse. Install sparse and use C=1.

After applying the patch #2, I tried to use C=1 yesterday, I double check it

today, still no warnings. Anything I missing?

quoted

$ make -j8 ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- W=1,C=1
  CALL    scripts/atomic/check-atomics.sh
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  CHK     kernel/kheaders_data.tar.xz
  CC [M]  drivers/net/ethernet/freescale/fec_main.o
  LD [M]  drivers/net/ethernet/freescale/fec.o
  MODPOST modules-only.symvers
  GEN     Module.symvers
  CC [M]  drivers/net/ethernet/freescale/fec.mod.o
  LD [M]  drivers/net/ethernet/freescale/fec.ko

Best Regards,
Joakim Zhang

quoted

     Andrew

If you look at
https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchw
ork.hopto.org%2Fstatic%2Fnipa%2F498729%2F12315211%2Fbuild_32bit%2Fst
dout&data=04%7C01%7Cqiangqing.zhang%40nxp.com%7Ce966882aff15
41ed54c108d931906ad2%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0
%7C637595318610458379%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjA
wMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&s
data=0o34i6pkvqBN1hPApz5Ja8CHjtqn8iwQB8whxg0p8Rw%3D&reserved
=0

you see:

Kernel: arch/x86/boot/bzImage is ready  (#9396)

So it is building for 32 bit x86. So try

make -j8 ARCH=i386 W=1 C=1

Assuming your host is an x86 machine.

Much thanks.

$ git am 0002-net-fec-add-ndo_select_queue-to-fix-TX-bandwidth-flu.patch
Applying: net: fec: add ndo_select_queue to fix TX bandwidth fluctuations
$ make -j8 ARCH=i386 W=1,C=1
  CALL    scripts/atomic/check-atomics.sh
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  CHK     kernel/kheaders_data.tar.xz
  CC [M]  drivers/net/ethernet/freescale/fec_main.o
  LD [M]  drivers/net/ethernet/freescale/fec.o
  MODPOST modules-only.symvers
Kernel: arch/x86/boot/bzImage is ready  (#1)
  GEN     Module.symvers
  CC [M]  drivers/net/ethernet/freescale/fec.mod.o
  LD [M]  drivers/net/ethernet/freescale/fec.ko

Unfortunately, I still can't see warnings after changing to build x86 image, a strange phenomenon, "W=1 C=1" seems not work, "W=1,C=1" can work.
I also save all of the build logs to double check, there is no build warnings related to FEC driver. 

Best Regards,
Joakim Zhang

	 Andrew