tree c91f5e841e5bef537feda5b75715412380dbe8c3
parent 1691ba3693d4b11cc85aed606d39ffbd23d8533f
author Willy Tarreau <w@1wt.eu> 1615370786 +0100
committer Willy Tarreau <w@1wt.eu> 1615371334 +0100
encoding latin1

OPTIM: task: automatically adjust the default runqueue-depth to the threads

The recent default runqueue size reduction appeared to have significantly
lowered performance on low-thread count configs. Testing various values
runqueue values on different workloads under thread counts ranging from
1 to 64, it appeared that lower values are more optimal for high thread
counts and conversely. It could even be drawn that the optimal value for
various workloads sits around 280/sqrt(nbthread), and probably has to do
with both the L3 cache usage and how to optimally interlace the threads'
activity to minimize contention. This is much easier to optimally
configure, so let's do this by default now.