[OE-core] [PATCH] populate_sdk_base: use xz -T instead of pixz

[Andre McCurdy]

On Mon, Apr 9, 2018 at 8:19 AM, Ross Burton <ross.burton at intel.com> wrote:
> xz has native support for threaded compression now and SDK creation was the only
> part of oe-core which is using pixz instead of xz.
>
> Not only does this remove pixz-native from the SDK dependencies, but in my
> limited testing xz -T0 is slightly faster and produces smaller archives than
> pixz for the same input.
>
> Signed-off-by: Ross Burton <ross.burton at intel.com>
> ---
>
>  # We want the MULTIARCH_TARGET_SYS to point to the TUNE_PKGARCH, not PACKAGE_ARCH as it
> @@ -225,7 +225,7 @@ fakeroot tar_sdk() {
>         # Package it up
>         mkdir -p ${SDKDEPLOYDIR}
>         cd ${SDK_OUTPUT}/${SDKPATH}
> -       tar ${SDKTAROPTS} -cf - . | pixz > ${SDKDEPLOYDIR}/${TOOLCHAIN_OUTPUTNAME}.tar.xz
> +       tar ${SDKTAROPTS} -cf - . | xz -T 0 > ${SDKDEPLOYDIR}/${TOOLCHAIN_OUTPUTNAME}.tar.xz

Since -T 0 will use all available CPUs (ie any attempts the user may
have made to limit parallelism via BB_NUMBER_THREADS or PARALLEL_MAKE
will be ignored), perhaps it's worth adding something like
"--memlimit=70%" to try to give some protection for environments with
lots of CPUs but not so much DRAM?