On Thu, Jan 14, 2021 at 01:05:33PM -0800, Yonghong Song wrote: > > > On 1/14/21 12:01 PM, Jiri Olsa wrote: > > On Thu, Jan 14, 2021 at 10:56:33AM -0800, Yonghong Song wrote: > > > > > > > > > On 1/14/21 5:40 AM, Jiri Olsa wrote: > > > > It's possible to have other build id types (other than default SHA1). > > > > Currently there's also ld support for MD5 build id. > > > > > > Currently, bpf build_id based stackmap does not returns the size of > > > the build_id. Did you see an issue here? I guess user space can check > > > the length of non-zero bits of the build id to decide what kind of > > > type it is, right? > > > > you can have zero bytes in the build id hash, so you need to get the size > > > > I never saw MD5 being used in practise just SHA1, but we added the > > size to be complete and make sure we'll fit with build id, because > > there's only limited space in mmap2 event > > I am asking to check whether we should extend uapi struct > bpf_stack_build_id to include build_id_size as well. I guess > we can delay this until a real use case. right, we can try make some MD5 build id binaries and check if it explodes with some bcc tools, but I don't expect that.. I'll try to find some time for that perf tool uses build ids in .debug cache as file links, and we had few isues there jirka
