Hello, Song. On Sat, Sep 14, 2019 at 03:02:51PM +0100, Song Liu wrote: > I think we don't need a perfect identifier in this case. IIUC, the goal of
I really don't want different versions of imperfect identifiers proliferating. > this patchset is to map each sample with a cgroup name (or full path). > To achieve this, we need > > 1. PERF_RECORD_CGROUP, that maps > "64-bit number" => cgroup name/path > 2. PERF_SAMPLE_CGROUP, that adds "64-bit number" to each sample. > > I call the id a "64-bit number" because it is not required to be a globally > unique id. As long as it is consistent within the same perf-record session, > we won't get any confusion. Since we add PERF_RECORD_CGROUP > for each cgroup creation, we will map most of samples correctly even > when the "64-bit number" is recycled within the same perf-record session. > > At the moment, I think ino is good enough for the "64-bit number" even > for 32-bit systems. If we don't call it "ino" (just call it "cgroup_tag" or > "cgroup_id", we can change it when kernfs provides a better 64-bit id. So, a firm nack on this direction. > About full path name: The user names the full path here. If the user gives > two different workloads the same name/path, we really cannot change that. > Reasonable users would be able to make sense from the full path. I don't see why we wanna be causing this avoidable problem to users. Thanks. -- tejun
