Em Fri, May 13, 2016 at 08:27:29AM -0600, David Ahern escreveu: > On 5/13/16 1:19 AM, Hekuang wrote: > > > What about putting the build id cache under the symfs? so instead of > > > dropping the symfs check and it to the path for the build id cache.
> > I think your intention is to reference symbol files in one place > > instead of two. So there're two possible approaches, one is all > > in buildid-cache, but in practice, I found lots of binaries in > > symfs even not contains valid buildid, so this way is not work. > > The other one is all in symfs. It seems ok, but one problem I > > should point out, with my test environment as an example, the > > symfsdir is $(TARGET_ROOTFS),and by default buildid_dir is > > $(TARGET_ROOTFS)/$(HOME)/.debug/, host perf does not know > > $(HOME) folder in target and we should copy the debug folder > > to $(TARGET_ROOTFS), which is readonly in the target. For me, it's > > easier to use 'buildid-cache -a vdso-xxxx' to add that into host > > buildid-cache than copy debug folder from $(HOME) to readonly > > $(TARGET_ROOTFS). > > Without the stale concern, I prefer the two places(buildid-dir in > > host and target symfs) way. > > The intention of symfs is every single file opened by perf is relative to > that directory. As I recall when I added that option in early 2011 I made > sure that statement is true. I think it is best to maintain that design. Ok, so we can introduce --dso-prefix for Hekuang's use case, i.e. be able to lookup by build-id, fallbacking to a (possibly read-only) directory. This way the existing --symfs semantic remains written in stone. - Arnaldo
