Files
sourcekit-lsp/Sources/BuildSystemIntegration/BuildSystemMessageDependencyTracker.swift
Alex Hoppen eb982d5b1e Fix quadratic performance issue in AsyncQueue<Serial>
Adding an item to `AsyncQueue` was linear in the number of pending queue items, thus adding n items to an `AsyncQueue` before any can execute is in O(n^2). This decision was made intentionally because the primary use case for `AsyncQueue` was to track pending LSP requests, of which we don’t expect to have too many pending requests at any given time.

While we can't fix the quadratic performance issue in general, we can resolve the quadratic issue of `AsyncQueue<Serial>` by making a new task only depend on the last item in the queue, which then transitively depends on all the previous items. `AsyncQueue<Serial>` are the queues that are most likely to contain many items.

Fixes #1725
rdar://137886469
2024-11-22 15:33:57 +01:00

121 lines
4.2 KiB
Swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#if compiler(>=6)
import BuildServerProtocol
package import LanguageServerProtocol
import LanguageServerProtocolExtensions
import SKLogging
package import SwiftExtensions
#else
import BuildServerProtocol
import LanguageServerProtocol
import LanguageServerProtocolExtensions
import SKLogging
import SwiftExtensions
#endif
/// A lightweight way of describing tasks that are created from handling BSP
/// requests or notifications for the purpose of dependency tracking.
package enum BuildSystemMessageDependencyTracker: QueueBasedMessageHandlerDependencyTracker {
/// A task that modifies some state. It is a barrier for all requests that read state.
case stateChange
/// A task that reads state, such as getting all build targets. These tasks can be run concurrently with other tasks
/// that read state but needs to wait for all state changes to be handled first.
case stateRead
/// A task that is responsible for logging information to the client. They can be run concurrently to any state read
/// and changes but logging tasks must be ordered among each other.
case taskProgress
/// Whether this request needs to finish before `other` can start executing.
package func isDependency(of other: BuildSystemMessageDependencyTracker) -> Bool {
switch (self, other) {
case (.stateChange, .stateChange): return true
case (.stateChange, .stateRead): return true
case (.stateRead, .stateChange): return true
case (.stateRead, .stateRead): return false
case (.taskProgress, .taskProgress): return true
case (.taskProgress, _): return false
case (_, .taskProgress): return false
}
}
package init(_ notification: some NotificationType) {
switch notification {
case is FileOptionsChangedNotification:
self = .stateChange
case is OnBuildExitNotification:
self = .stateChange
case is OnBuildInitializedNotification:
self = .stateChange
case is OnBuildLogMessageNotification:
self = .taskProgress
case is OnBuildTargetDidChangeNotification:
self = .stateChange
case is OnWatchedFilesDidChangeNotification:
self = .stateChange
case is TaskFinishNotification:
self = .taskProgress
case is TaskProgressNotification:
self = .taskProgress
case is TaskStartNotification:
self = .taskProgress
default:
logger.error(
"""
Unknown notification \(type(of: notification)). Treating as a stateChange notification. \
This might lead to sub-optimal performance because it inhibits parallelism.
"""
)
self = .stateRead
}
}
package func dependencies(in pendingTasks: [PendingTask<Self>]) -> [PendingTask<Self>] {
return pendingTasks.filter { $0.metadata.isDependency(of: self) }
}
package init(_ request: some RequestType) {
switch request {
case is BuildShutdownRequest:
self = .stateChange
case is BuildTargetPrepareRequest:
self = .stateRead
case is BuildTargetSourcesRequest:
self = .stateRead
case is TaskStartNotification, is TaskProgressNotification, is TaskFinishNotification:
self = .taskProgress
case is InitializeBuildRequest:
self = .stateChange
case is RegisterForChanges:
self = .stateChange
case is TextDocumentSourceKitOptionsRequest:
self = .stateRead
case is WorkspaceBuildTargetsRequest:
self = .stateRead
case is WorkspaceWaitForBuildSystemUpdatesRequest:
self = .stateRead
default:
logger.error(
"""
Unknown request \(type(of: request)). Treating as a stateChange request. \
This might lead to sub-optimal performance because it inhibits parallelism.
"""
)
self = .stateChange
}
}
}