[OE-core] [PATCH v2] classes/populate_sdk_base: Implement xz compression options

[Mike Looijmans]

Building an SDK on a machine with 8GB RAM resulted in excessive swapping
due to the xz compressor using ~20GB of memory. This is because xz is
being called with "-T 0 -9".

To allow tuning the compression versus memory usage, introduce a variable
named SDK_XZ_OPTIONS that defaults to a more sane default:
SDK_XZ_OPTIONS ?= "${XZ_DEFAULTS} ${SDK_XZ_COMPRESSION_LEVEL}"
The use of XZ_DEFAULTS fixes the excessive memory usage.
The SDK_XZ_COMPRESSION_LEVEL variable allows overriding the speed vs
compression. In an office or development environment the extra time
spent on compressing a few percent more is just not worth it.

Signed-off-by: Mike Looijmans <mike.looijmans at topic.nl>
---
 meta/classes/populate_sdk_base.bbclass | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/meta/classes/populate_sdk_base.bbclass b/meta/classes/populate_sdk_base.bbclass
index d03465b6fc..179ed93979 100644
--- a/meta/classes/populate_sdk_base.bbclass
+++ b/meta/classes/populate_sdk_base.bbclass
@@ -48,6 +48,8 @@ TOOLCHAIN_OUTPUTNAME ?= "${SDK_NAME}-toolchain-${SDK_VERSION}"
 
 # Default archived SDK's suffix
 SDK_ARCHIVE_TYPE ?= "tar.xz"
+SDK_XZ_COMPRESSION_LEVEL ?= "-9"
+SDK_XZ_OPTIONS ?= "${XZ_DEFAULTS} ${SDK_XZ_COMPRESSION_LEVEL}"
 
 # To support different sdk type according to SDK_ARCHIVE_TYPE, now support zip and tar.xz
 python () {
@@ -58,7 +60,7 @@ python () {
        d.setVar('SDK_ARCHIVE_CMD', 'cd ${SDK_OUTPUT}/${SDKPATH}; zip -r ${SDKDEPLOYDIR}/${TOOLCHAIN_OUTPUTNAME}.${SDK_ARCHIVE_TYPE} .')
     else:
        d.setVar('SDK_ARCHIVE_DEPENDS', 'xz-native')
-       d.setVar('SDK_ARCHIVE_CMD', 'cd ${SDK_OUTPUT}/${SDKPATH}; tar ${SDKTAROPTS} -cf - . | xz -T 0 -9 > ${SDKDEPLOYDIR}/${TOOLCHAIN_OUTPUTNAME}.${SDK_ARCHIVE_TYPE}')
+       d.setVar('SDK_ARCHIVE_CMD', 'cd ${SDK_OUTPUT}/${SDKPATH}; tar ${SDKTAROPTS} -cf - . | xz ${SDK_XZ_OPTIONS} > ${SDKDEPLOYDIR}/${TOOLCHAIN_OUTPUTNAME}.${SDK_ARCHIVE_TYPE}')
 }
 
 SDK_RDEPENDS = "${TOOLCHAIN_TARGET_TASK} ${TOOLCHAIN_HOST_TASK}"
-- 
2.17.1