Poor scaling

[Frank Ch. Eigler]

Josh Stone <jistone@redhat.com> writes:

> [...]  I think I'd rather see this explicit declared on the global
> itself, instead of treating tid() specially.  Something like the
> proposed percpu globals:
> https://sourceware.org/bugzilla/show_bug.cgi?id=10795

Or even more like https://sourceware.org/bugzilla/show_bug.cgi?id=10796

> The challenge is how to allocate and free that per-task memory, and how
> to look up that memory from arbitrary probe context.  It's possible,
> just not entirely trivial.

... and to make it more efficient than the current code!  One can
imagine hooking into tracepoints to track task lifetimes, and create
some tid-indexed rcu hash tables or somesuch.  Kind of like the
kretprobes data-pouches.  Possible, just a SMOP.  We should probably
reopen PR10796 and give it a real try.


- FChE