On 11/1/18 2:52 PM, Gregg Reynolds wrote: > On Mon, Oct 29, 2018, 6:30 PM Mats Wichmann <m...@wichmann.us> wrote: > >> >> Hi, folks. I'm still around even if not very active, wanted to run >> something by you all. >> >> While working on the scons project, something else I do on the side, I >> notice people keep asking about the caching capabilities of SCons. Some >> are able to use it to considerable benefit. >> >> Tl:dr version of caching: if there exists in the cache a file which >> could be used instead of building a target, use the cached version. >> > > Sorry, I think this is very misleading. Scons "caching" really means > something like "shared remote caching", with multiple devs sharing the > cache. https://scons.org/doc/1.3.0/HTML/scons-user/c4154.html > > Or maybe that's not what you mean, dunno. Seems obvious that every build > system involves caching in some way.
it appears very few scons projects in the wild use what that page calls shared cache. scons does use some "caching" even if not asked to... for example it keeps some "autoconf-like" results from run to run, and it keeps signatures of all derived files stored away in a lightweight database to help it determine if they need to be rebuilt. But other than the act of storing the signatures itself, I wouldn't call the latter caching, just part of computing whether to rebuild or not. Perhaps it's semantics: if foo.o is still in your build tree and you don't rebuild foo.o as a I don't equate that with "fetch from cache"... am I still being obtuse? For developers to share builds using the scons sharing scheme, they have to share a machine; who does that any more? Well, I know it happens... but when your codevelopers are halfway around the world and their build machines are behind corporate firewalls of different companies? So I'm only noodling on about this in the context of the CI system. Where each build is a freshly provisioned machine with no object files left behind from a previous build, whatever you call that you end up building every derived file each time. (*) Note: current version of that page is here: https://scons.org/doc/3.0.1/HTML/scons-user.html#chap-caching I don't think there's been any real change in behavior * Footnote: apparently, before the CI system switched to provision-on-demand instances, it used persistent images with the ccache tool installed on the Linux machines, so it was getting a caching effect from that. that was external to scons. that capability no longer applies. -=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#9990): https://lists.iotivity.org/g/iotivity-dev/message/9990 Mute This Topic: https://lists.iotivity.org/mt/27787640/21656 Group Owner: iotivity-dev+ow...@lists.iotivity.org Unsubscribe: https://lists.iotivity.org/g/iotivity-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
