Backport: Re-factor to fix high CPU usage on windows (#1562) #1598
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This decouples getting the basic state information from getting the more
detailed information. The reason is that filtering only needs the name, but
the code was getting all details and then apply filtering. Getting the command
line is expensive on Windows, so that contributed to #1460.
What made it worse is that due to filtering, the command line cache was
invalidated on each run, which explains why topbeat was consuming more CPU when
filtering out processes than when not.
Fixes #1460.
This also pre-compiles the regexps, which brings some slight CPU usage improvements
and uncovers compilation errors earlier.