From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Sun, 28 Jun 2015 23:00:02 +0200 Subject: [Buildroot] [RFC v4 00/16] Add per-package staging feature In-Reply-To: <20150628204622.GE3950@free.fr> References: <1435520570-20332-1-git-send-email-fabio.porcedda@gmail.com> <20150628204622.GE3950@free.fr> Message-ID: <20150628230002.608893c0@free-electrons.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Yann E. MORIN, On Sun, 28 Jun 2015 22:46:22 +0200, Yann E. MORIN wrote: > > | 35GB | 99m | master branch > > | 37GB | 100m | patch set > > | 153GB | 105m | patch set using hard links only for the toolchain sysroot > > | 225GB | 106m | patch set not using hardlinks at all > > > > Test about performances of this patch set vs master branch: > > | 199m | HW-MED | defconfig-full | master branch | no top-level make | > > | 99m | HW-MED | defconfig-full | master branch | top-level make | > > | 100m | HW-MED | defconfig-full | patch set | top-level make | > > > > | 350m | HW-HIGH | defconfig-full | master branch | no top-level make | > > | 73m | HW-HIGH | defconfig-full | master branch | top-level make | > > | 77m | HW-HIGH | defconfig-full | patch set | top-level make | > > > > | 10m | HW-MED | defconfig-small | master branch | no top-level make | > > | 5m | HW-MED | defconfig-small | master branch | top-level make | > > | 5m | HW-MED | defconfig-samll | patch set | top-level make | > > > > | 21m18s | HW-HIGH | defconfig-small | master branch | no top-level make | > > | 7m53s | HW-HIGH | defconfig-small | master branch | top-level make | > > | 7m54s | HW-HIGH | defconfig-samll | patch set | top-level make | > > OK, so those benchmarks show that: > > - HDD are terribly slow when compared to SSDs Yes, and the top-level parallel make gives the highest benefit on HDDs: from 350m to 77m and from 21m to 8m on the HW-HIGH configuration. > - the build-time overhead is low, 5% in the worst case (73min -> 77min) Yes. > - the size overhead is huge, a factor 4.4 with hardlinks, 6.5 without > hardlinks No, as you replied, the size overhead is very reasonable. You misread Fabio's table here. > - we're missing the benchmarks for this patchset without top-level > parallel make (especially for the size overhead). Unless it no > longer makes sense? Correct, I asked the same thing. > So, I'm really a bit skeptical. About five time the size for only about > twice the speedup, is it worth it? Sure some people will easily favour > speed over anything else, still the size overhead is really huge. Do you reconsider this comment now that you know the reality about the size impact ? :-) > Otherwise, I have a 2x4 core Xeon @3.4GHz with three SSDs in RAID0 which > might be better as a HW_HIGH system. I can spin a test-build with this > patchset on this machine to see what we get... Would definitely be useful. Maybe Fabio can provide you his defconfig-full test case (he gave the defconfig-small case). Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com