In the current statistics counter implementation, the statistics are
backed by an array of counters, which are updated via atomic operations.
This leads to contention, especially on high core count
machines.
This commit introduces a new isc_statsmulti_t counter that keeps a
separate array per thread. These counters are then aggregated only when
statistics are queried, shifting work off the critical path.
These changes lead to a ~2% improvement in perflab.
Returning the value allows for better high-water tracking without
running into edge cases like the following:
0. The counter is at value X
1. Increment the value (X+1)
2. The value is decreased multiple times in another threads (X+1-Y)
3. Get the value (X+1-Y)
4. Update-if-greater misses the X+1 value which should have been the
high-water
The isc_stats_create() can no longer return anything else than
ISC_R_SUCCESS. Refactor isc_stats_create() and its variants in libdns,
libns and named to just return void.
This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
4708. [cleanup] Legacy Windows builds (i.e. for XP and earlier)
are no longer supported. [RT #45186]
4707. [func] The lightweight resolver daemon and library (lwresd
and liblwres) have been removed. [RT #45186]
4706. [func] Code implementing name server query processing has
been moved from bin/named to a new library "libns".
Functions remaining in bin/named are now prefixed
with "named_" rather than "ns_". This will make it
easier to write unit tests for name server code, or
link name server functionality into new tools.
[RT #45186]
