od: use -O3

[glebm]

No description provided.

[SnDream]

Here are the results of my test.
-O3: can keep gambatte running Mental Respirator at full speed with frameskip.
-fipa-pta: one scene in Mental Respirator has sound flickering, but it looks better than without this parameter (personal subjective feeling).

PS: Dingoonity was closed recently, where else can I get more information about OpenDingux?

[glebm]

So I guess we should go with #112, which has both -O3 and -fipa-pta (LTO has no effect as it only affects a few irrelevant packages).
While most system packages make no difference, I'm guessing the main speedup comes from SDL being compiled with these flags.

[glebm]

PS: Dingoonity was closed recently, where else can I get more information about OpenDingux?

I'm guessing you're on the Discord already but in case you're not: https://discord.gg/t7GeHScr

[glebm]

Rebased, so now the build in this PR has both -fipa-pta and -O3

[glebm]

@pcercuei Let's merge this?

[glebm]

Actually, shall we enable this for all systems, not just the rs90?

[glebm]

Now enabled on all systems, similar to #115

[pcercuei]

Can we have more tests with various games / apps, and emulators that don't use dynarecs (e.g. PocketSNES)?

[glebm]

This doesn't change the compilation flags for emulators nor the kernel, just the buildroot packages. The improvement likely comes from SDL. So I'm guessing SDL blitting functions get more optimized or something like that.

I don't have 2 devices to run side-by-side, if someone does please do test! 🙏

[citral23]

I haven't been able to measure any meaningful difference between just -fipa-pta and -fipa-pta + -O3, neither on the rs90 nor a rg350m

It's possible the difference seen was unrelated to -O3, it's after all rather doubtful that it would introduce a dramatic improvement at blitting, that's not generally how things work (it barely does anything, or even worsens emulators perfs, so I doubt OS itself would have a clear benefit personnally)