Support measuring terminal proc latency

src/vs/workbench/api/browser/mainThreadTerminalService.ts

@@ -8,6 +8,7 @@ import { ITerminalService, ITerminalInstance, IShellLaunchConfig, ITerminalProce
 import { ExtHostContext, ExtHostTerminalServiceShape, MainThreadTerminalServiceShape, MainContext, IExtHostContext, ShellLaunchConfigDto } from 'vs/workbench/api/common/extHost.protocol';
 import { extHostNamedCustomer } from 'vs/workbench/api/common/extHostCustomers';
 import { UriComponents, URI } from 'vs/base/common/uri';
+import { StopWatch } from 'vs/base/common/stopwatch';
 
 @extHostNamedCustomer(MainContext.MainThreadTerminalService)
 export class MainThreadTerminalService implements MainThreadTerminalServiceShape {
@@ -227,6 +228,7 @@ export class MainThreadTerminalService implements MainThreadTerminalServiceShape
 		request.proxy.onShutdown(immediate => this._proxy.$acceptProcessShutdown(request.proxy.terminalId, immediate));
 		request.proxy.onRequestCwd(() => this._proxy.$acceptProcessRequestCwd(request.proxy.terminalId));
 		request.proxy.onRequestInitialCwd(() => this._proxy.$acceptProcessRequestInitialCwd(request.proxy.terminalId));
+		request.proxy.onRequestLatency(() => this._onRequestLatency(request.proxy.terminalId));
 	}
 
 	public $sendProcessTitle(terminalId: number, title: string): void {
@@ -253,4 +255,16 @@ export class MainThreadTerminalService implements MainThreadTerminalServiceShape
 	public $sendProcessCwd(terminalId: number, cwd: string): void {
 		this._terminalProcesses[terminalId].emitCwd(cwd);
 	}
+
+	private async _onRequestLatency(terminalId: number): Promise<void> {
+		const COUNT = 2;
+		let sum = 0;
+		for (let i = 0; i < COUNT; i++) {
+			const sw = StopWatch.create(true);
+			await this._proxy.$acceptProcessRequestLatency(terminalId);
+			sw.stop();
+			sum += sw.elapsed();
+		}
+		this._terminalProcesses[terminalId].emitLatency(sum / COUNT);
+	}
 }

src/vs/workbench/api/common/extHost.protocol.ts

@@ -1041,6 +1041,7 @@ export interface ExtHostTerminalServiceShape {
 	$acceptProcessShutdown(id: number, immediate: boolean): void;
 	$acceptProcessRequestInitialCwd(id: number): void;
 	$acceptProcessRequestCwd(id: number): void;
+	$acceptProcessRequestLatency(id: number): number;
 }
 
 export interface ExtHostSCMShape {

src/vs/workbench/api/node/extHostTerminalService.ts

@@ -529,6 +529,10 @@ export class ExtHostTerminalService implements ExtHostTerminalServiceShape {
 		this._terminalProcesses[id].getCwd().then(cwd => this._proxy.$sendProcessCwd(id, cwd));
 	}
 
+	public $acceptProcessRequestLatency(id: number): number {
+		return id;
+	}
+
 	private _onProcessExit(id: number, exitCode: number): void {
 		// Remove listeners
 		this._terminalProcesses[id].dispose();

src/vs/workbench/contrib/terminal/browser/terminalProcessManager.ts

@@ -27,6 +27,11 @@ import { IRemoteEnvironmentService } from 'vs/workbench/services/remote/common/r
 /** The amount of time to consider terminal errors to be related to the launch */
 const LAUNCHING_DURATION = 500;
 
+/**
+ * The minimum amount of time between latency requests.
+ */
+const LATENCY_MEASURING_INTERVAL = 1000;
+
 /**
  * Holds all state related to the creation and management of terminal processes.
  *
@@ -46,6 +51,9 @@ export class TerminalProcessManager implements ITerminalProcessManager {
 	private _process: ITerminalChildProcess | null = null;
 	private _preLaunchInputQueue: string[] = [];
 	private _disposables: IDisposable[] = [];
+	private _latency: number = -1;
+	private _latencyRequest: Promise<number>;
+	private _latencyLastMeasured: number = 0;
 
 	private readonly _onProcessReady = new Emitter<void>();
 	public get onProcessReady(): Event<void> { return this._onProcessReady.event; }
@@ -77,6 +85,7 @@ export class TerminalProcessManager implements ITerminalProcessManager {
 				c(undefined);
 			});
 		});
+		this.ptyProcessReady.then(async () => await this.getLatency());
 	}
 
 	public dispose(immediate: boolean = false): void {
@@ -240,6 +249,18 @@ export class TerminalProcessManager implements ITerminalProcessManager {
 		return this._process.getCwd();
 	}
 
+	public async getLatency(): Promise<number> {
+		if (!this._process) {
+			return Promise.resolve(0);
+		}
+		if (this._latencyLastMeasured === 0 || this._latencyLastMeasured + LATENCY_MEASURING_INTERVAL < Date.now()) {
+			this._latencyRequest = this._process.getLatency();
+			this._latency = await this._latencyRequest;
+			this._latencyLastMeasured = Date.now();
+		}
+		return Promise.resolve(this._latency);
+	}
+
 	private _onExit(exitCode: number): void {
 		this._process = null;
 

src/vs/workbench/contrib/terminal/common/terminal.ts

@@ -654,6 +654,7 @@ export interface ITerminalProcessManager extends IDisposable {
 
 	getInitialCwd(): Promise<string>;
 	getCwd(): Promise<string>;
+	getLatency(): Promise<number>;
 }
 
 export const enum ProcessState {
@@ -685,12 +686,14 @@ export interface ITerminalProcessExtHostProxy extends IDisposable {
 	emitExit(exitCode: number): void;
 	emitInitialCwd(initialCwd: string): void;
 	emitCwd(cwd: string): void;
+	emitLatency(latency: number): void;
 
 	onInput: Event<string>;
 	onResize: Event<{ cols: number, rows: number }>;
 	onShutdown: Event<boolean>;
 	onRequestInitialCwd: Event<void>;
 	onRequestCwd: Event<void>;
+	onRequestLatency: Event<void>;
 }
 
 export interface ITerminalProcessExtHostRequest {
@@ -733,4 +736,5 @@ export interface ITerminalChildProcess {
 
 	getInitialCwd(): Promise<string>;
 	getCwd(): Promise<string>;
+	getLatency(): Promise<number>;
 }
\ No newline at end of file

src/vs/workbench/contrib/terminal/common/terminalProcessExtHostProxy.ts

@@ -31,9 +31,12 @@ export class TerminalProcessExtHostProxy implements ITerminalChildProcess, ITerm
 	public get onRequestInitialCwd(): Event<void> { return this._onRequestInitialCwd.event; }
 	private readonly _onRequestCwd = new Emitter<void>();
 	public get onRequestCwd(): Event<void> { return this._onRequestCwd.event; }
+	private readonly _onRequestLatency = new Emitter<void>();
+	public get onRequestLatency(): Event<void> { return this._onRequestLatency.event; }
 
 	private _pendingInitialCwdRequests: ((value?: string | Thenable<string>) => void)[] = [];
 	private _pendingCwdRequests: ((value?: string | Thenable<string>) => void)[] = [];
+	private _pendingLatencyRequests: ((value?: number | Thenable<number>) => void)[] = [];
 
 	constructor(
 		public terminalId: number,
@@ -86,6 +89,12 @@ export class TerminalProcessExtHostProxy implements ITerminalChildProcess, ITerm
 		}
 	}
 
+	public emitLatency(latency: number): void {
+		while (this._pendingLatencyRequests.length > 0) {
+			this._pendingLatencyRequests.pop()!(latency);
+		}
+	}
+
 	public shutdown(immediate: boolean): void {
 		this._onShutdown.fire(immediate);
 	}
@@ -111,4 +120,11 @@ export class TerminalProcessExtHostProxy implements ITerminalChildProcess, ITerm
 			this._pendingCwdRequests.push(resolve);
 		});
 	}
+
+	public getLatency(): Promise<number> {
+		return new Promise<number>(resolve => {
+			this._onRequestLatency.fire();
+			this._pendingLatencyRequests.push(resolve);
+		});
+	}
 }
\ No newline at end of file

src/vs/workbench/contrib/terminal/node/terminalProcess.ts

@@ -213,4 +213,8 @@ export class TerminalProcess implements ITerminalChildProcess, IDisposable {
 			resolve(this._initialCwd);
 		});
 	}
+
+	public getLatency(): Promise<number> {
+		return Promise.resolve(0);
+	}
 }