tree 3cd62d6aaf78290d197131f0283096cee9dcc647
parent b20aa9eef354b5cca3f9ea43aab38d568e7fdeb7
author Willy Tarreau <w@1wt.eu> 1539612768 +0200
committer Willy Tarreau <w@1wt.eu> 1539623173 +0200
encoding latin1

OPTIM: tasks: group all tree roots per cache line

Currently we have per-thread arrays of trees and counts, but these
ones unfortunately share cache lines and are accessed very often. This
patch moves the task-specific stuff into a structure taking a multiple
of a cache line, and has one such per thread. Just doing this has
reduced the cache miss ratio from 19.2% to 18.7% and increased the
12-thread test performance by 3%.

It starts to become visible that we really need a process-wide per-thread
storage area that would cover more than just these parts of the tasks.
The code was arranged so that it's easy to move the pieces elsewhere if
needed.