[LEDE-DEV] [OpenWrt-Devel] latency on PPPoA ADSL Annex A on using Lantiq

Wed Aug 17 22:33:13 PDT 2016

i would guess a regression inside the atm subsystem of he kernel or some
other part of the network stack. assuming that this issue is only
observed inside the atm part, i'll start looking there.

	John

On 18/08/2016 06:22, Daniel Niasoff wrote:
> Hi Mathias,
> 
> 
> Looks like it's this commit that introduced the issue
> 
> 
> https://git.openwrt.org/openwrt.git?p=openwrt.git;a=commitdiff;h=f9eb558f08c577d216d39c25d0572facc18a3ac1
> 
> 
> -KERNEL_PATCHVER:=3.18
> +KERNEL_PATCHVER:=4.1
> 
> must be something in version 4.1 kernel. I guess it doesn't help very  much.
> 
> 
> I tried to downgrade the latest commit back to a version 3.18 kernel by
> reversing the above change but wasn't able to compile. I had this error
> 
> 
> make -f ./scripts/Makefile.build
> obj=/home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9
>   mips-openwrt-linux-musl-gcc
> -Wp,-MD,/home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9/.ltq_atm.o.d
>  -nostdinc -isystem
> /home/build/openwrt/staging_dir/toolchain-mips_34kc+dsp_gcc-5.3.0_musl-1.1.14/lib/gcc/mips-openwrt-linux-musl/5.3.0/include
> -I./arch/mips/include -Iarch/mips/include/generated  -Iinclude
> -I./arch/mips/include/uapi -Iarch/mips/include/generated/uapi
> -I./include/uapi -Iinclude/generated/uapi -include
> ./include/linux/kconfig.h -D__KERNEL__
> -DVMLINUX_LOAD_ADDRESS=0xffffffff88002000 -DDATAOFFSET=0 -Wall -Wundef
> -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common
> -Werror-implicit-function-declaration -Wno-format-security -std=gnu89
> -mno-check-zero-division -mabi=32 -G 0 -mno-abicalls -fno-pic -pipe
> -mno-branch-likely -msoft-float -DGAS_HAS_SET_HARDFLOAT -Wa,-msoft-float
> -ffreestanding -march=r4600 -Wa,--trap
> -I./arch/mips/include/asm/mach-ip22
> -I./arch/mips/include/asm/mach-generic -fno-delete-null-pointer-checks
> -O2 -fno-reorder-blocks -fno-tree-ch -fno-caller-saves
> --param=allow-store-data-races=0 -Wframe-larger-than=1024
> -fstack-protector -Wno-unused-but-set-variable -fomit-frame-pointer
> -fno-var-tracking-assignments -g -femit-struct-debug-baseonly
> -fno-var-tracking -Wdeclaration-after-statement -Wno-pointer-sign
> -fno-strict-overflow -fconserve-stack -Werror=implicit-int
> -Werror=strict-prototypes -Werror=date-time -DCC_HAVE_ASM_GOTO  -DMODULE
> -mno-long-calls -DCONFIG_VR9 -D"KBUILD_STR(s)=#s"
> -D"KBUILD_BASENAME=KBUILD_STR(ltq_atm)"
>  -D"KBUILD_MODNAME=KBUILD_STR(ltq_atm_vr9)" -c -o
> /home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9/ltq_atm.o
> /home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9/ltq_atm.c
> /home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9/ltq_atm.c:46:24:
> fatal error: lantiq_soc.h: No such file or directory
> compilation terminated.
> make[5]: ***
> [/home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9/ltq_atm.o]
> Error 1
> make[4]: ***
> [_module_/home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9]
> Error 2
> make[4]: Leaving directory
> `/home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/linux-3.18.29'
> make[3]: ***
> [/home/build/openwrt/build_dir/target-mips_34kc+dsp_musl-1.1.14/linux-lantiq_xrx200/ltq-atm-vr9/.built]
> Error 2
> make[3]: Leaving directory
> `/home/build/openwrt/package/kernel/lantiq/ltq-atm'
> make[2]: *** [package/kernel/lantiq/ltq-atm/compile] Error 2
> make[2]: Leaving directory `/home/build/openwrt'
> make[1]: ***
> [/home/build/openwrt/staging_dir/target-mips_34kc+dsp_musl-1.1.14/stamp/.package_compile]
> Error 2
> make[1]: Leaving directory `/home/build/openwrt'
> 
> Thanks
> 
> Daniel
> 
> 
> 
> 
> 
> 
> 
> ------------------------------------------------------------------------
> *From:* Mathias Kresin <dev at kresin.me>
> *Sent:* 10 August 2016 22:39
> *To:* Daniel Niasoff
> *Cc:* openwrt-devel at lists.openwrt.org; lede-dev at lists.infradead.org;
> (leon at darkk.net.ru)
> *Subject:* Re: [OpenWrt-Devel] latency on PPPoA ADSL Annex A on using
> Lantiq
>  
> Am 10.08.2016 um 22:41 schrieb Daniel Niasoff:
>> Hi Mathias,
>>
>>  ADSL works fine on chaos calmer and I cannot reproduce the issue, so it looks like it's a recently introduced issue.
>>
>> Thanks for the idea, it should make it easier to pinpoint
>>
>> Any idea's where the issue might be?
> 
> Nope, no idea yet. Might be a kernel update or something completely
> unexpected. Without knowing the commit that introduced the regression
> it's more or less crystal ball reading.
> 
> Using 'git bisect' it should be easy to identify the faulty commit. It
> has to be somewhere between the last commit before chaos calmer was
> branched (git hash 6c9b1a278e484a9c7c5ff36f91da90f725776d00) and HEAD.
> 
> git bisect tells me that you have to build and test circa 12 images to
> find the faulty commit:
> 
> git clone "https://github.com/openwrt/openwrt.git"
> <https://github.com/openwrt/openwrt.git>
> 	
> openwrt/openwrt <https://github.com/openwrt/openwrt.git>
> github.com
> openwrt - Linux distribution for embedded devices
> 
> 
> 
> git checkout master
> git bisect start HEAD 6c9b1a278e484a9c7c5ff36f91da90f725776d00
> Bisecting: 1688 revisions left to test after this (roughly 11 steps)
> 
> It might be a good idea to verify that
> 6c9b1a278e484a9c7c5ff36f91da90f725776d00 is not affected by the bug
> before starting the bisect.
> 
> Mathias
> 
> 
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