Commit 4b576670 authored by Eric S. Raymond's avatar Eric S. Raymond
Browse files

An observation about performance.

parent 25b55509
Pipeline #8924865 passed with stage
in 5 minutes and 34 seconds
......@@ -171,6 +171,16 @@ at protocol handling, packets arriving faster than the main loop could
cycle would pile up in the ring buffer and latecomers would be
dropped.
(Also, it turns out not to be important at post-Y2K machine speeds to
get those arrival timestamps from the UDP layer ASAP, rather than
looking at packet read time in userspace. The cost of the latter,
naive approach is additional jitter dominated by process-scheduling
time. This used to be significant relative to users' accuracy
expectations for NTP, but scheduler timeslices have since decreased
by orders of magnitude and squashed the issue. We know this from some
tests setup having run for six months with packet-timestamp fetching
accidentally disabled...)
The new organization stops pretending; it simply spins on a select
across all interfaces. If inbound traffic is more than the daemon can
handle, packets will pile up in the UDP layer and be dropped at that
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment