commit 4fa7c6c7431b8c35730680cf6cd03d2df0b85f1a
author Lalit Maganti <lalitm@google.com> Wed Feb 06 15:06:36 2019 +0000
committer Lalit Maganti <lalitm@google.com> Wed Feb 06 15:06:36 2019 +0000
tree 1aa4c824bdad1f71bd644c04eff875fa5cd45914
parent 71b40a07a007a995bee17af078c3543f447b41f0

trace_processor: overhaul and reenable args and raw tables

This CL reintroduces the args table but with args deduped by "arg set".

An arg set is a collection of args which appear together. Since it is
very common for a group of args to appear together with the same values.
For example, the args for sched_switch where swapper -> process A or
the extreme case where regardless of how many CPU idle events there are,
there will only be 32 possible pairs of (idle state, cpu) for a 8 CPU
machine.

Thus, for each arg set we create, we can hash it, see if it's already
in the args table and if so we just refer to that existing set.

The logic for this is done by a newly introduced class ArgTracker which
buffers args being added for each row of another table and flushes to
storage at the end of the packet.

We also need to add columns to raw and counters tables to allow them to
reference the arg set in the args table.

Bug: 122513680
Change-Id: I1e99fa9eda3054b16ca48f0aaf03dde47fbbbdce