Eric Sandeen wrote: > I had found some tools once to do static callchain analysis & graph > them, maybe time to break it out again. codeviz was the tool; getting it to work is fiddly. But here, for example, are some of the callers of ext4_mb_init_cache() (one of the functions at the bottom of your deep chain), with stack usage and piggish ones highlighted in red: http://sandeen.fedorapeople.org/ext4/ext4_mb_init_cache_callers.png This is actually only analysis of the functions in mballoc.c, but that's relevant for the static / noinline decisions. The stack usage values were after my attempt to get gcc to inline -nothing- at all. So there you can see that ext4_mb_regular_allocator by itself uses 104 bytes, but calls several other functions which get inlined normally: ext4_mb_try_best_found 16 ext4_mb_try_by_goal 56 ext4_mb_load_buddy 24 ext4_mb_init_group 24 Without all the noinlining, ext4_mb_regular_allocator uses 232 bytes ... 104+16+56+24+24 = 224 is close to that. On the flip side here are the functions called by ext4_mb_init_cache_callees within mballoc.c: http://sandeen.fedorapeople.org/ext4/ext4_mb_init_cache_callees.png Here too I think you can see that if much of that gets inlined, it'll bloat that function. A bit more analysis like this might yield some prudent changes ... but it's tedious. :) -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
