buildroot: Speed up build times #38
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support/scripts/setlocalversion within Buildroot's source is run when make print-version is called, which gets information about the boot-utils repository, not Buildroot, resulting in the version check failing and always redownloading the Buildroot source, even when it is not necessary. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
fakeroot 1.25.3 does not build with glibc 2.33 currently so add the upstream Buildroot patch that adds fakeroot upstream patches to resolve this. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
nathanchance
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msfjarvis,
nickdesaulniers and
tpimh
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msfjarvis
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Mar 15, 2021
| BR2_TOOLCHAIN_EXTERNAL=y | ||
| BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y | ||
| BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_ARMV5_EABI_UCLIBC_STABLE=y | ||
| BR2_TARGET_GENERIC_ROOT_PASSWD="root" | ||
| BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0" | ||
| BR2_ROOTFS_OVERLAY="../overlay-reboot" | ||
| BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y | ||
| BR2_PACKAGE_BASH=y |
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What shell do we boot to with -i? I assume we still have one, it's just whatever busybox has which I don't think is Bash?
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I use this with -i a lot, so I'm just checking this doesn't break that.
nickdesaulniers
approved these changes
Mar 15, 2021
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I was thinking about this more overnight: does using ccache really speed up builds? I would expect to add to build time, unless you were to rebuild multiple images in repetition. Given how infrequently we update these, is it worth using ccache? Or does it somehow speed up the build regardless? I don't see how it would, unless some of the same code is being rebuilt for each image. Since we're cross compiling, I'd expect many cache misses even for the same source inputs. |
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Yes, as Dima said, we have always been using busybox's ash except for on PowerPC it seems. Unless you were manually running Well, the prebuilt toolchains are infrequently updated so they should have some cache hits and the cache location is in |
This saves cycles while rebuilding the images. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This saves cycles while rebuilding the images. We need to switch off software floating point emulation so that the prebuilt toolchain can be selected. This should not impact anything as all of the kernels that we build have CONFIG_MIPS_FP_SUPPORT, which emulates an FPU if there is not one present. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
We are going to be specifying POWER8 as the target architecture for our 64-bit PowerPC builds to allow us to use a prebuilt Bootlin toolchain to build our rootfs images. To compliment that, emulate a POWER8 CPU so that there are no issues when we get to userspace. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This saves cycles while rebuilding the images. For 32-bit, we need to switch to the 440fp variant so that the prebuilt toolchain can be selected. This does not impact anything because the kernel builds FP emulation for targets that do not have an FPU (which it seems like bamboo does from my research anyways). For 64-bit, we need to switch to the power8 variant so that the prebuilt toolchain can be selected. We can boot QEMU with a power8 CPU so this does not affect anything either. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This saves cycles while rebuilding the images. We need to switch to the LP64 ABI so that the prebuilt toolchain can be selected. This is a soft float ABI, which is not the biggest deal because this rootfs will always be run under emulation so performance is not the biggest deal. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Use newer versions of GCC and binutils to generate better code. There is no prebuilt toolchain available for this target. The glibc components are dropped because they are the default. s390 does not have any other libc support. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This saves cycles while rebuilding the images. We switch to the i686 subarchitecture so that the prebuilt toolchain can be selected. This still passes all of my 32-bit x86 build tests. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
We are going to update our x86_64 rootfs image to be able to be built with a prebuilt toolchain to speed up builds of the rootfs images, which will require at least SSE 4.2 support. This CPU is the microarchitecture of the first Core i7 processor, which will be the target for Buildroot. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This saves cycles while rebuilding the images. We switch to the corei7 target so that the prebuilt toolchain can be selected. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
To help slim down images after upgrading the compiler implicitly by moving to Bootlin's prebuilt toolchains, use -Os instead of -O3 and do not build bash. We were not even using bash by default aside from on PowerPC and these images are meant for quick smoke tests. In depth debugging is better done using the Debian support that boot-utils offers or by rebuilding one of the images with EDITCONFIG=1 set. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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Alright, should be good, PTAL. |
nickdesaulniers
approved these changes
Mar 15, 2021
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Switch to prebuilt toolchains wherever possible and use ccache.
All of the individual commits should be self explanatory but heckle me as necessary :)