packages.Load slows *everything* down even though it is in a separate thread (go mod mode)

[rcoreilly]

editing has become very jerky, when adding new lines -- the root cause seems to be from packages.Load -- here's a relevant ticket:

golang/go#29427

I just switched code back to previous GoSrcDir for GOPATH mode and it is now smooth again..

This should all be on a separate go routine so not clear why it is affecting performance so much -- I'll investigate..

[rcoreilly]

current status: using delayed markup for everything greatly reduces, but does not eliminate, this issue. is it GC? need to add some additional diagnostics so can file a ticket with tools.

[rcoreilly]

Looks like something is kinda broken here also -- can't seem to find dependencies in wwi3d in go mod mode -- needs a significant revisit.

[rcoreilly]

Here's some useful info about why packages.Load is so slow: golang/go#31087 (comment)

And example using golang.org/x/tools/mod/module instead -- the tricky issue here is of course finding the versions.

Just realized the best way to deal with this is to just create our own internal cache of path names! The first time you hit packages.Load it will be slow, but after that, it will be fast..

[rcoreilly]

yeah that fixes it! modules mode now works!