internal/lsp/cache: cache known subdirs pattern
Known subdirs change rarely and it's quite expensive to compute
a glob pattern derived from them, so cache computation result
and inherit it across generations.
Computation cost is divided ≈evenly between `sort.Sort` and
`span.URI.Filename` calls, and there is no trivial way to optimize
them away besides caching.
Benchmark (didChange in kubernetes): ~37ms->30ms
Change-Id: Idb1691c76b8ff163dc61f637f07229498888606c
GitHub-Last-Rev: cd99a9ce5c797afb5aaa9b478fcf433edd0dc03c
GitHub-Pull-Request: golang/tools#383
Reviewed-on: https://go-review.googlesource.com/c/tools/+/411636
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/internal/lsp/cache/snapshot.go b/internal/lsp/cache/snapshot.go
index 6edd1db..7b73f4b 100644
--- a/internal/lsp/cache/snapshot.go
+++ b/internal/lsp/cache/snapshot.go
@@ -114,7 +114,8 @@
// knownSubdirs is the set of subdirectories in the workspace, used to
// create glob patterns for file watching.
- knownSubdirs map[span.URI]struct{}
+ knownSubdirs map[span.URI]struct{}
+ knownSubdirsPatternCache string
// unprocessedSubdirChanges are any changes that might affect the set of
// subdirectories in the workspace. They are not reflected to knownSubdirs
// during the snapshot cloning step as it can slow down cloning.
@@ -834,21 +835,38 @@
// of the directories in the workspace. We find them by adding the
// directories of every file in the snapshot's workspace directories.
// There may be thousands.
- knownSubdirs := s.getKnownSubdirs(dirs)
- if n := len(knownSubdirs); n > 0 {
- dirNames := make([]string, 0, n)
- for _, uri := range knownSubdirs {
- dirNames = append(dirNames, uri.Filename())
- }
- sort.Strings(dirNames)
- // The double allocation of Sprintf(Join()) accounts for 8%
- // of DidChange, but specializing doesn't appear to help. :(
- patterns[fmt.Sprintf("{%s}", strings.Join(dirNames, ","))] = struct{}{}
+ if pattern := s.getKnownSubdirsPattern(dirs); pattern != "" {
+ patterns[pattern] = struct{}{}
}
return patterns
}
+func (s *snapshot) getKnownSubdirsPattern(wsDirs []span.URI) string {
+ s.mu.Lock()
+ defer s.mu.Unlock()
+
+ // First, process any pending changes and update the set of known
+ // subdirectories.
+ // It may change list of known subdirs and therefore invalidate the cache.
+ s.applyKnownSubdirsChangesLocked(wsDirs)
+
+ if len(s.knownSubdirs) == 0 {
+ return ""
+ }
+
+ if s.knownSubdirsPatternCache == "" {
+ dirNames := make([]string, 0, len(s.knownSubdirs))
+ for uri := range s.knownSubdirs {
+ dirNames = append(dirNames, uri.Filename())
+ }
+ sort.Strings(dirNames)
+ s.knownSubdirsPatternCache = fmt.Sprintf("{%s}", strings.Join(dirNames, ","))
+ }
+
+ return s.knownSubdirsPatternCache
+}
+
// collectAllKnownSubdirs collects all of the subdirectories within the
// snapshot's workspace directories. None of the workspace directories are
// included.
@@ -859,6 +877,7 @@
defer s.mu.Unlock()
s.knownSubdirs = map[span.URI]struct{}{}
+ s.knownSubdirsPatternCache = ""
for uri := range s.files {
s.addKnownSubdirLocked(uri, dirs)
}
@@ -870,6 +889,16 @@
// First, process any pending changes and update the set of known
// subdirectories.
+ s.applyKnownSubdirsChangesLocked(wsDirs)
+
+ result := make([]span.URI, 0, len(s.knownSubdirs))
+ for uri := range s.knownSubdirs {
+ result = append(result, uri)
+ }
+ return result
+}
+
+func (s *snapshot) applyKnownSubdirsChangesLocked(wsDirs []span.URI) {
for _, c := range s.unprocessedSubdirChanges {
if c.isUnchanged {
continue
@@ -881,12 +910,6 @@
}
}
s.unprocessedSubdirChanges = nil
-
- result := make([]span.URI, 0, len(s.knownSubdirs))
- for uri := range s.knownSubdirs {
- result = append(result, uri)
- }
- return result
}
func (s *snapshot) addKnownSubdirLocked(uri span.URI, dirs []span.URI) {
@@ -917,6 +940,7 @@
}
s.knownSubdirs[uri] = struct{}{}
dir = filepath.Dir(dir)
+ s.knownSubdirsPatternCache = ""
}
}
@@ -929,6 +953,7 @@
}
if info, _ := os.Stat(dir); info == nil {
delete(s.knownSubdirs, uri)
+ s.knownSubdirsPatternCache = ""
}
dir = filepath.Dir(dir)
}
@@ -1816,6 +1841,7 @@
for k, v := range s.knownSubdirs {
result.knownSubdirs[k] = v
}
+ result.knownSubdirsPatternCache = s.knownSubdirsPatternCache
for _, c := range changes {
result.unprocessedSubdirChanges = append(result.unprocessedSubdirChanges, c)
}
