Hi Linus, 2018-03-11 3:44 GMT+09:00 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>: > On Sat, Mar 10, 2018 at 5:48 AM, Masahiro Yamada > <yamada.masahiro@xxxxxxxxxxxxx> wrote: >> >> Please pull more Kbuild fixes for v4.16. > > Pulled. > > And I really don't think these are the reason, but I wonder if you've > looked at why an empty build seems to have become slower lately? > > I do "allmodconfig" builds between each pull, and it used to be in the > 40+ second range. Now it's in the "just over a minute" range. That's > with absolutely nothing actually being built. > > That "nothing rebuilt" is actually the big expense for me for the > later -rc handling, since it completely dominates when the pull > requests shrink (even if *something* gets rebuilt, the one minute for > the empty build is 90+% of the time). > > It might not be kbuild that has triggered this, it might be something > else. But some trivial profiling shows that it's definitely pretty > much all in make, although 'modpost' does show up: > > 83.18% make > 11.30% modpost > 5.10% sh > 0.31% cat > 0.03% cc1 > 0.01% grep > ... > > The above was just from > > perf record -e cycles:pp make -j16 > > and then doing a > > perf report --sort=comm > > to see a very high-level overview. > > Pretty much all of the time in 'make' is spent on parsing, it seems: > > 5.24% make [.] hash_find_slot > 3.86% make [.] __strlen_avx2 > 3.76% make [.] _int_malloc > 3.25% make [.] target_environment > 2.82% make [.] __memmove_avx_unaligned_erms > 2.49% make [.] __strcmp_sse2_unaligned > 2.41% modpost [.] parse_file > 2.21% make [.] malloc > 2.18% make [.] 0x000000000001e1f3 > 2.10% make [.] glob > 2.06% make [.] __strchr_avx2 > 1.92% make [.] parse_variable_definition > 1.76% make [.] _int_free > 1.52% make [.] parse_file_seq > 1.49% make [.] find_next_token > .... > > and maybe it's 'make' that has gotten upgraded and slowed down, and > it's not our build system at all. > > Yes, my build times continually do go up as the kernel grows, so > that's normal. It's just that there seems to have been a fairly big > jump in the last month or so. > > I haven't tried to bisect anything, I thought I'd just mention it in > case you go "yeah, I'm aware.." No. I am not aware of it. I tried empty building for several tags. The build time was almost constant for me. I saw about increase by 6 seconds between v4.15 between v4.16-rc1, but I think this is quite normal. The full log of my experiments are below: [1] v4.15-rc1 masahiro@pug:~/workspace/linux$ git describe v4.15-rc1 masahiro@pug:~/workspace/linux$ time make all CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h CHK include/generated/bounds.h CHK include/generated/timeconst.h CHK include/generated/asm-offsets.h CALL scripts/checksyscalls.sh DESCEND objtool CHK scripts/mod/devicetable-offsets.h CHK include/generated/compile.h CHK kernel/config_data.h CHK include/generated/uapi/linux/version.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#38) Building modules, stage 2. MODPOST 6586 modules WARNING: modpost: missing MODULE_LICENSE() in drivers/auxdisplay/img-ascii-lcd.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-ath79.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-iop.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/accel/kxsd9-i2c.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/adc/qcom-vadc-common.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/mtk-vcodec/mtk-vcodec-common.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/soc_camera/soc_scale_crop.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/tegra-cec/tegra_cec.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/mtd/nand/denali_pci.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/pinctrl/pxa/pinctrl-pxa2xx.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/power/reset/zx-reboot.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/staging/comedi/drivers/ni_atmio.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in net/9p/9pnet_xen.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in sound/soc/codecs/snd-soc-pcm512x-spi.o see include/linux/module.h for more information real 1m42.019s user 1m12.828s sys 0m19.732s [2] v4.15 masahiro@pug:~/workspace/linux$ git describe v4.15 masahiro@pug:~/workspace/linux$ time make all CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h CHK include/generated/bounds.h CHK include/generated/timeconst.h CHK include/generated/asm-offsets.h CALL scripts/checksyscalls.sh DESCEND objtool CHK scripts/mod/devicetable-offsets.h CHK include/generated/compile.h CHK kernel/config_data.h CHK include/generated/uapi/linux/version.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#33) Building modules, stage 2. MODPOST 6585 modules WARNING: modpost: missing MODULE_LICENSE() in drivers/auxdisplay/img-ascii-lcd.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-ath79.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/gpio/gpio-iop.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/accel/kxsd9-i2c.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/iio/adc/qcom-vadc-common.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/mtk-vcodec/mtk-vcodec-common.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/soc_camera/soc_scale_crop.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/tegra-cec/tegra_cec.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/mtd/nand/denali_pci.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/pinctrl/pxa/pinctrl-pxa2xx.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in drivers/power/reset/zx-reboot.o see include/linux/module.h for more information WARNING: modpost: missing MODULE_LICENSE() in sound/soc/codecs/snd-soc-pcm512x-spi.o see include/linux/module.h for more information real 1m41.114s user 1m12.596s sys 0m19.416s [3] v4.16-rc1 masahiro@pug:~/workspace/linux$ git describe v4.16-rc1 masahiro@pug:~/workspace/linux$ time make all CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h CHK include/generated/bounds.h CHK include/generated/timeconst.h CHK include/generated/asm-offsets.h CALL scripts/checksyscalls.sh DESCEND objtool CHK scripts/mod/devicetable-offsets.h CHK include/generated/compile.h CHK kernel/config_data.h CHK include/generated/uapi/linux/version.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#37) Building modules, stage 2. MODPOST 6666 modules real 1m47.057s user 1m15.952s sys 0m21.496s [4] v4.16-rc2 masahiro@pug:~/workspace/linux$ git describe v4.16-rc2 masahiro@pug:~/workspace/linux$ time make all CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h CHK include/generated/bounds.h CHK include/generated/timeconst.h CHK include/generated/asm-offsets.h CALL scripts/checksyscalls.sh DESCEND objtool CHK scripts/mod/devicetable-offsets.h CHK include/generated/compile.h CHK kernel/config_data.h CHK include/generated/uapi/linux/version.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#36) Building modules, stage 2. MODPOST 6666 modules real 1m47.064s user 1m15.916s sys 0m21.640s [5] v4.16-rc5 masahiro@pug:~/workspace/linux$ git describe v4.16-rc5 masahiro@pug:~/workspace/linux$ time make all CHK include/config/kernel.release CHK include/generated/uapi/linux/version.h CHK include/generated/utsrelease.h CHK include/generated/bounds.h CHK include/generated/timeconst.h CHK include/generated/asm-offsets.h CALL scripts/checksyscalls.sh DESCEND objtool CHK scripts/mod/devicetable-offsets.h CHK include/generated/compile.h CHK kernel/config_data.h CHK include/generated/uapi/linux/version.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#35) Building modules, stage 2. MODPOST 6664 modules real 1m47.242s user 1m15.576s sys 0m22.088s -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
