On Wed, Oct 06, 2021 at 10:41:41AM +0200, Jiri Olsa wrote: > hi, > I'm hitting performance issue and soft lock ups with the new version > of the patchset and the reason seems to be kallsyms lookup that we > need to do for each btf id we want to attach ugh, I meant to sent this as reply to the patchset mentioned above, nevermind, here's the patchset: https://lore.kernel.org/bpf/20210605111034.1810858-1-jolsa@xxxxxxxxxx/ jirka > > I tried to change kallsyms_lookup_name linear search into rbtree search, > but it has its own pitfalls like duplicate function names and it still > seems not to be fast enough when you want to attach like 30k functions > > so I wonder we could 'fix this' by storing function address in BTF, > which would cut kallsyms lookup completely, because it'd be done in > compile time > > my first thought was to add extra BTF section for that, after discussion > with Arnaldo perhaps we could be able to store extra 8 bytes after > BTF_KIND_FUNC record, using one of the 'unused' bits in btf_type to > indicate that? or new BTF_KIND_FUNC2 type? > > thoughts? > > thanks, > jirka
