On Thu 22-09-16 11:30:36, Janani Ravichandran wrote: > > > On Sep 19, 2016, at 5:42 AM, Michal Hocko <mho...@kernel.org> wrote: > > > > On Tue 13-09-16 14:04:49, Janani Ravichandran wrote: > >> > >>> On Sep 12, 2016, at 8:16 AM, Michal Hocko <mho...@kernel.org> wrote: > >> > >> I’m using the function graph tracer to see how long > >> __alloc_pages_nodemask() > >> took. > > > > How can you map the function graph tracer to a specif context? Let's say > > I would like to know why a particular allocation took so long. Would > > that be possible? > > Maybe not. If the latencies are due to direct reclaim or memory compaction, > you > get some information from the tracepoints (like > mm_vmscan_direct_reclaim_begin, > mm_compaction_begin, etc). But otherwise, you don’t get any context > information. > Function graph only gives the time spent in alloc_pages_nodemask() in that > case.
Then I really think that we need a starting trace point. I think that having the full context information is really helpful in order to understand latencies induced by allocations. -- Michal Hocko SUSE Labs
