The unix specification for unix sockets only allocates ~100 characters
for the length of the path. This may be longer than the path for a CI
runner, or the path to a user's buildstream directory.

Add pre-merge tests that use a WSL runner

Closes #852

See merge request !1108

Daniel Silverstone authored Feb 06, 2019 and Benjamin Schubert committed Feb 06, 2019

The licence for roaringbitmap was not compatible.  pyroaring is
a similar project which is MIT licensed and is slightly better on
memory too.

Signed-off-by: Daniel Silverstone <daniel.silverstone@codethink.co.uk>

loadelement.py: Switch from roaringbitmap to pyroaring

Closes #899

See merge request !1133

We were indiscriminately retrieving the node's provenance data in the
`node_get()` function which was accounting for approximately a third of
the total runtime of `node_get()` which dominates pre-scheduler time in
`bst build`.  This change ameliorates that situation by only retrieving
the provenance data when it's actually needed.

Signed-off-by: Daniel Silverstone <daniel.silverstone@codethink.co.uk>

We know that nodes are typically one of:
str, list, dict, bool, tuple, NoneType or our ChainMap
Of these, dict and ChainMap are Mapping, only list is list
and the rest are returned unchanged.  We can reduce/defer our use
of isinstance here, dramatically, improving performance.

Signed-off-by: Daniel Silverstone <daniel.silverstone@codethink.co.uk>

In order to support a case where the caller already has pre-sanitized input
this variant of the cache key generator needs to exist.

Signed-off-by: Daniel Silverstone <daniel.silverstone@codethink.co.uk>

In order to reduce the effort we spend in `_yaml.node_sanitize()` take
advantage of how `OrderedDict` works and pre-sanitize the majority of
the cache-key once.  This approximately halves the amount of effort we
spend in `_yaml.node_sanitize()` in pre-scheduler build scenarios.

Signed-off-by: Daniel Silverstone <daniel.silverstone@codethink.co.uk>

A non-trivial proportion of time pre-scheduler in `bst build` is spent
copying (or chain-copying) nodes.  Approximately a quarter of the time
spent in that effort is in `isinstance()`.  This removes that CPU load.

Signed-off-by: Daniel Silverstone <daniel.silverstone@codethink.co.uk>