Do I understand correctly?
That the main idea is that using the Parts a big project is split into
many small parts.
And then SCons builds these parts more-or-less independently.
I.e. SCons processes many small DAGs instead of one big DAG.
Thank you.
Best regards,
Constantine.
On 01/23/15 18:03, Kenny, Jason L wrote:
I understand this problem. This is one main thing Parts tries to
address. It uses information about the different component to figure
out what not to load. This requires the build to be laid out in some
sort of component based like build, vs a recursive make, which may not
be a big deal, depending on how your project is laid out. The result
for example of a massive build I have here is a “do nothing” build
takes ~7-20 second vs the normal ~15-20 minutes it would normally
take. Incremental build also are reduced to minutes ( depending on
what changed of course)
I honestly believe this can be better yet.. but we requires more
work. The main issue with spawn issue that we pushed, was found when
a build for this large product moved from rhel4 to rhel5. The time
increased from 2 hours to 4+. It was the spawning issue. Something
changed that really made this worse. Once we had this fixed rhel5
build went to 2 hours and the old rhel4 based build went to ~1.5 hours.
Jason
*From:*Scons-dev [mailto:scons-dev-boun...@scons.org] *On Behalf Of
*Tom Tanner (BLOOMBERG/ LONDON)
*Sent:* Thursday, January 22, 2015 2:49 AM
*To:* scons-dev@scons.org
*Subject:* Re: [Scons-dev] SCons-like build system
Having been poking around in this, I see that 'posix_spawn' cleans to
be availble on both aix and solaris (at least they have man pages).
Which is a relief for me. However, my current grief is that a 'do
nothing' build is still taking 20 minutes to traverse the tree. *part*
of this is because I check the md5sum on each file to make sure
someone hasn't gone and edit/patched/hacked a generated target (which
happens more often than is desirable), but that isn't the bulk of the
time taken.
I suspect I could leverage the fact that we use git to get the sha1 of
certain repositories that are known not to be changed by us and if we
find a file therein, to use the combined sha1 of the repos might
improve that at the cost of potentially spurious rebuilds if one of
the repos changed but the others didn't as i wouldn't be reading all
the files.
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