On Wed, Apr 08, 2020 at 02:27:02PM +0200, Nils Wallménius wrote: > Hi, been away from rb for a couple of years but one thing that might be > worthwhile is to "re tune" the compiler flags for the codecs when changing > toolchain. Basically just build the whole bunch with O[123] and run the > test files through test_codec for each arc. Of course it's not necessary up > front but would make it fairly easy to spot serious perf regressions and to > get any benefits from better optimizers.
Oh, cleaning up the compiler flags is definitely on my to-do list, but I lack access to a sufficiently diverse set of targets to do much benchmarking (or much general testing) myself. As part of the WIP toolchain patch in gerrit [1], I changed the global CFLAGS to include "-Os -Wall -Wextra -funit-at-a-time", and have been fixing up the warnings that have come up. Some of these turned out to be very real bugs. Meanwhile, the CODECs (and a few of the plugins [2]) are the only things remaining that override the global optimization flags, but the bootloaders tend to force -Os for obvious reasons. There are also plugins that blanket-disable all warnings [3]. IMO we should use -Os for everything, and only use -O2 or -O3 if benchmarks show a tangible benefit (and the code still fits, obviously). If -Os causes problems then we should disable the specific problematic optimizations rather than downgrade to -O1 or -O0. [1] http://gerrit.rockbox.org/r/#/c/2305/ [2] SDL and xzbox, notably, though several others force -Os already [3] SDL and puzzles. I have a WIP patch trying to clean up SDL too [4] [4] http://gerrit.rockbox.org/r/#/c/2324/ > Glad to see people still working on it. ...Suffice it to say I could really use some help getting this done. - Solomon -- Solomon Peachy pizza at shaftnet dot org High Springs, FL ^^ (email/xmpp) ^^ Quidquid latine dictum sit, altum videtur.
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