On 03/10/2020 08:37, Chris Johns wrote:
On 2/10/20 5:53 am, Joel Sherrill wrote:
On Thu, Oct 1, 2020 at 2:39 PM Sebastian Huber
<sebastian.hu...@embedded-brains.de
<mailto:sebastian.hu...@embedded-brains.de>>
wrote:
On 01/10/2020 20:09, Joel Sherrill wrote:
> What was the rationale behind the choice of the default for the number
> of jobs for the waf build system?
I don't know. It is the default behaviour of waf. I noticed also
scalability problems but had no time to track them down. It could be
also a limitation of the Python multiprocessing capabilities. I am also
not a waf expert, I may have produced some bottlenecks.
I don't think you produced any bottlenecks. Here are a couple of fragments
from my build. I have attached the ini file so you can double check that it
does match. Please let me know if the ini matches the configure command
or not. If it doesn't, then I have a lot of bogus builds. :(
../rtems/configure --target=arm-rtems6 --enable-rtemsbsp=gumstix
--prefix=/home/joel/rtems-cron-6/tools/6/bsp-install --disable-networking
--enable-posix --disable-smp --disable-multiprocessing --enable-rtems-debug
--enable-profiling --enable-tests --enable-cxx --enable-maintainer-mode
+ make -j24
real 1m53.064s
user 7m14.675s
sys 1m45.913s
.....
+ ./waf -j 24
real 1m1.404s
user 0m9.601s
sys 0m1.547s
Notice how the build time for waf is 50 seconds faster but that doesn't
match the user and system time. Perhaps the Python jobs model doesn't
keep them as children the same way so time doesn't get to count them.
I honestly can't explain that.
Which host OS?
I am running a waf build of 5 BSPs with tests on FreeBSD 12.1 and I ran `systat
-vmstat 1` at the same time and it shows idle is around 0%, 25% is in sys and
75% is in user. The machine has with 8 cores. The powerpc/mvme5500 took 58
seconds. Python is 3.7.6.
I noticed the scalability issues on systems with more than 64 processors
of the GCC compile farm.
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