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Move running tasks for fixed time to the scheduler.

Browse source 
This improves recovery time for change/undo from 300 ms to 200 ms for
analyzer + analysis_server + front_end.

_FilesReferencingNameTask does not degrade in any noticeble way, it is
still about 0-1 ms for this code base, as compared to 60 ms without
fixing runing time in the task or the scheduler.

R=brianwilkerson@google.com, paulberry@google.com
BUG=

Review URL: https://codereview.chromium.org/2540403002 .
This commit is contained in:
Konstantin Shcheglov 2016-12-01 09:15:36 -08:00
parent aaaeee5bc4
commit 53b04631bc
1 changed files with 48 additions and 38 deletions
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86
pkg/analyzer/lib/src/dart/analysis/driver.dart
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@ -918,6 +918,27 @@ enum AnalysisDriverPriority {
* work with the highest priority is performed first.
*/
class AnalysisDriverScheduler {
/**
* Time interval in milliseconds before pumping the event queue.
*
* Relinquishing execution flow and running the event loop after every task
* has too much overhead. Instead we use a fixed length of time, so we can
* spend less time overall and still respond quickly enough.
*/
static const int _MS_BEFORE_PUMPING_EVENT_QUEUE = 2;
/**
* Event queue pumping is required to allow IO and other asynchronous data
* processing while analysis is active. For example Analysis Server needs to
* be able to process `updateContent` or `setPriorityFiles` requests while
* background analysis is in progress.
*
* The number of pumpings is arbitrary, might be changed if we see that
* analysis or other data processing tasks are starving. Ideally we would
* need to run all asynchronous operations using a single global scheduler.
*/
static const int _NUMBER_OF_EVENT_QUEUE_PUMPINGS = 128;
final PerformanceLog _logger;
final List<AnalysisDriver> _drivers = [];
final Monitor _hasWork = new Monitor();
@ -977,18 +998,14 @@ class AnalysisDriverScheduler {
* priority first.
*/
Future<Null> _run() async {
Stopwatch timer = new Stopwatch()..start();
PerformanceLogSection analysisSection;
while (true) {
// Pump the event queue to allow IO and other asynchronous data
// processing while analysis is active. For example Analysis Server
// needs to be able to process `updateContent` or `setPriorityFiles`
// requests while background analysis is in progress.
//
// The number of pumpings is arbitrary, might be changed if we see that
// analysis or other data processing tasks are starving. Ideally we
// would need to be able to set priority of (continuous) asynchronous
// tasks.
await _pumpEventQueue(128);
// Pump the event queue.
if (timer.elapsedMilliseconds > _MS_BEFORE_PUMPING_EVENT_QUEUE) {
await _pumpEventQueue(_NUMBER_OF_EVENT_QUEUE_PUMPINGS);
timer.reset();
}
await _hasWork.signal;
@ -1266,38 +1283,31 @@ class _FilesReferencingNameTask {
_FilesReferencingNameTask(this.driver, this.name);
/**
* Perform work for a fixed length of time, and either complete the
* [completer] and return `true` to indicate that the task is done, return
* `false` to indicate that the task should continue to be run.
*
* Relinquishing execution flow and running event loop after every file
* works, but has too much overhead. Instead we use a fixed length of time,
* so we can spend less time overall and keep quick enough response time.
* Perform a single piece of work, and either complete the [completer] and
* return `true` to indicate that the task is done, return `false` to indicate
* that the task should continue to be run.
*/
Future<bool> perform() async {
Stopwatch timer = new Stopwatch()..start();
while (timer.elapsedMilliseconds < 5) {
// Prepare files to check.
if (filesToCheck.isEmpty) {
Set<String> newFiles = driver.addedFiles.difference(checkedFiles);
filesToCheck.addAll(newFiles);
}
// If no more files to check, complete and done.
if (filesToCheck.isEmpty) {
completer.complete(referencingFiles);
return true;
}
// Check the next file.
String path = filesToCheck.removeLast();
FileState file = driver._fsState.getFileForPath(path);
if (file.referencedNames.contains(name)) {
referencingFiles.add(path);
}
checkedFiles.add(path);
// Prepare files to check.
if (filesToCheck.isEmpty) {
Set<String> newFiles = driver.addedFiles.difference(checkedFiles);
filesToCheck.addAll(newFiles);
}
// If no more files to check, complete and done.
if (filesToCheck.isEmpty) {
completer.complete(referencingFiles);
return true;
}
// Check the next file.
String path = filesToCheck.removeLast();
FileState file = driver._fsState.getFileForPath(path);
if (file.referencedNames.contains(name)) {
referencingFiles.add(path);
}
checkedFiles.add(path);
// We're not done yet.
return false;
}