On 05/13/2015 12:17 PM, Ingo Molnar wrote: >>> In any case, the interesting measurement would not be -Os comparisons >>> (which causes GCC to be too crazy), but to see the size effect of your >>> _patch_ that always-inlines spinlock ops, on plain defconfig and on >>> defconfig-Os. >> >> Here it is: >> >> text data bss dec hex filename >> 12335864 1746152 1081344 15163360 e75fe0 vmlinuxO2.before >> 12335930 1746152 1081344 15163426 e76022 vmlinux > > Hm, that's a (small) size increase on O2. > > That might be a net positive though: because now we've eliminated > quite a few function calls. Do we know which individual functions > bloat and which debloat?
>> text data bss dec hex filename >> 10373764 1684200 1077248 13135212 c86d6c vmlinuxOs.before >> 10363621 1684200 1077248 13125069 c845cd vmlinux > > A decrease - which gets exploded on allyesconfig. > > So as long as the -O2 case does not get hurt we can do -Os fixes. > > I think this needs a bit more work to ensure that the O2 case is a net > win. I think O2 difference is just noise: with -O2 gcc is far less prone to bogus deinlining, my patch should have negligible effect. And effect is indeed negligible: +70 bytes on 12 megabytes. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
