Re: [PATCH v2 11/12] .travis.yml: probe for number of available processors

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

(Cc'ing Ed Vielmetti)

On 1/30/20 12:32 PM, Alex Bennée wrote:
> The arm64 hardware was especially hit by only building on 3 of the 32
> available cores. Introduce a JOBS environment variable which we use
> for all parallel builds. We still run the main checks single threaded
> though so to make it easier to spot hangs.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> ---
>   .travis.yml | 20 +++++++++++---------
>   1 file changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/.travis.yml b/.travis.yml
> index 1b92f40eab..a600f508b0 100644
> --- a/.travis.yml
> +++ b/.travis.yml
> @@ -85,6 +85,8 @@ git:
>   # Common first phase for all steps
>   before_install:
>     - if command -v ccache ; then ccache --zero-stats ; fi
> +  - export JOBS=$(($(getconf _NPROCESSORS_ONLN) + 1))

Yeah finally!

Note, on the Cavium ThunderX CN88XX provided by Packet, Ed Vielmetti 
once suggested to use the --load-average make option due to Amdahl's 
law, and I noticed a minor speedup using -j96 -l47.5 (-l48 already 
starts to decrease).

On https://docs.travis-ci.com/user/reference/overview/#linux I read
"LXD compliant OS images for arm64 are run in Packet."

Per 
https://travis-ci.community/t/what-machine-s-does-travis-use-for-arm64/5579/2 
the CPU seems to be a Ampere eMAG Skylark:
https://en.wikichip.org/wiki/apm/microarchitectures/skylark
Probably the eMAG 8180:
https://en.wikichip.org/wiki/ampere_computing/emag/8180

I don't know what would be the best limit for this CPU.

Back to this patch, it indeed reduced the build time by 2+, so:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> +  - echo "=== Using ${JOBS} simultaneous jobs ==="
>   
>   # Configure step - may be overridden
>   before_script:
> @@ -93,7 +95,7 @@ before_script:
>   
>   # Main build & test - rarely overridden - controlled by TEST_CMD
>   script:
> -  - BUILD_RC=0 && make -j3 || BUILD_RC=$?
> +  - BUILD_RC=0 && make -j${JOBS} || BUILD_RC=$?
>     - if [ "$BUILD_RC" -eq 0 ] ; then travis_retry ${TEST_CMD} ; else $(exit $BUILD_RC); fi
>   after_script:
>     - if command -v ccache ; then ccache --show-stats ; fi
> @@ -125,7 +127,7 @@ matrix:
>         env:
>           - BASE_CONFIG="--enable-tools"
>           - CONFIG="--disable-user --disable-system"
> -        - TEST_CMD="make check-unit check-softfloat -j3"
> +        - TEST_CMD="make check-unit check-softfloat -j${JOBS}"
>           - CACHE_NAME="${TRAVIS_BRANCH}-linux-gcc-default"
>   
>   
> @@ -160,13 +162,13 @@ matrix:
>       - name: "check-unit coroutine=ucontext"
>         env:
>           - CONFIG="--with-coroutine=ucontext --disable-tcg"
> -        - TEST_CMD="make check-unit -j3 V=1"
> +        - TEST_CMD="make check-unit -j${JOBS} V=1"
>   
>   
>       - name: "check-unit coroutine=sigaltstack"
>         env:
>           - CONFIG="--with-coroutine=sigaltstack --disable-tcg"
> -        - TEST_CMD="make check-unit -j3 V=1"
> +        - TEST_CMD="make check-unit -j${JOBS} V=1"
>   
>   
>       # Check we can build docs and tools (out of tree)
> @@ -366,7 +368,7 @@ matrix:
>       - name: "GCC check-tcg (user)"
>         env:
>           - CONFIG="--disable-system --enable-debug-tcg"
> -        - TEST_CMD="make -j3 check-tcg V=1"
> +        - TEST_CMD="make -j${JOBS} check-tcg V=1"
>           - CACHE_NAME="${TRAVIS_BRANCH}-linux-gcc-debug-tcg"
>   
>   
> @@ -375,7 +377,7 @@ matrix:
>       - name: "GCC plugins check-tcg (user)"
>         env:
>           - CONFIG="--disable-system --enable-plugins --enable-debug-tcg --target-list-exclude=sparc64-linux-user"
> -        - TEST_CMD="make -j3 check-tcg V=1"
> +        - TEST_CMD="make -j${JOBS} check-tcg V=1"
>           - CACHE_NAME="${TRAVIS_BRANCH}-linux-gcc-debug-tcg"
>   
>   
> @@ -383,7 +385,7 @@ matrix:
>       - name: "GCC check-tcg (some-softmmu)"
>         env:
>           - CONFIG="--enable-debug-tcg --target-list=xtensa-softmmu,arm-softmmu,aarch64-softmmu,alpha-softmmu"
> -        - TEST_CMD="make -j3 check-tcg V=1"
> +        - TEST_CMD="make -j${JOBS} check-tcg V=1"
>           - CACHE_NAME="${TRAVIS_BRANCH}-linux-gcc-debug-tcg"
>   
>   
> @@ -391,7 +393,7 @@ matrix:
>       - name: "GCC plugins check-tcg (some-softmmu)"
>         env:
>           - CONFIG="--enable-plugins --enable-debug-tcg --target-list=xtensa-softmmu,arm-softmmu,aarch64-softmmu,alpha-softmmu"
> -        - TEST_CMD="make -j3 check-tcg V=1"
> +        - TEST_CMD="make -j${JOBS} check-tcg V=1"
>           - CACHE_NAME="${TRAVIS_BRANCH}-linux-gcc-debug-tcg"
>   
>       - name: "[aarch64] GCC check-tcg"
> @@ -500,7 +502,7 @@ matrix:
>           - BUILD_DIR="release/build/dir" SRC_DIR="../../.."
>           - BASE_CONFIG="--prefix=$PWD/dist"
>           - CONFIG="--target-list=x86_64-softmmu,aarch64-softmmu,armeb-linux-user,ppc-linux-user"
> -        - TEST_CMD="make install -j3"
> +        - TEST_CMD="make install -j${JOBS}"
>           - QEMU_VERSION="${TRAVIS_TAG:1}"
>           - CACHE_NAME="${TRAVIS_BRANCH}-linux-gcc-default"
>         script:
>