From 6a7c5e15763c6e61eb35e5a09771969eaccc1c9b Mon Sep 17 00:00:00 2001
From: Ilya Chernikov <ilya.chernikov@jetbrains.com>
Date: Wed, 7 Oct 2015 12:56:45 +0200
Subject: [PATCH] Reducing overhead of rpc callbacks by 1) subsampling
 cancelled status check (had severe impact), and 2) using buffered remote
 message streams (had less but still noticeable impact)

---
 .../kotlin/rmi/service/CompileServiceImpl.kt  | 19 +++++++++++++------
 .../RemoteCompilationCanceledStatusClient.kt  | 11 ++++++++++-
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/CompileServiceImpl.kt b/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/CompileServiceImpl.kt
index 8da7cbee995..b1a323ffbac 100644
--- a/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/CompileServiceImpl.kt
+++ b/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/CompileServiceImpl.kt
@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.config.Services
 import org.jetbrains.kotlin.load.kotlin.incremental.components.IncrementalCompilationComponents
 import org.jetbrains.kotlin.progress.CompilationCanceledStatus
 import org.jetbrains.kotlin.rmi.*
+import java.io.BufferedOutputStream
 import java.io.PrintStream
 import java.rmi.NoSuchObjectException
 import java.rmi.registry.Registry
@@ -130,12 +131,18 @@ class CompileServiceImpl(
     private fun doCompile(args: Array<out String>, compilerMessagesStreamProxy: RemoteOutputStream, serviceOutputStreamProxy: RemoteOutputStream, body: (PrintStream, Profiler) -> ExitCode): Int =
             ifAlive {
                 val rpcProfiler = if (daemonOptions.reportPerf) WallAndThreadTotalProfiler() else DummyProfiler()
-                val compilerMessagesStream = PrintStream(RemoteOutputStreamClient(compilerMessagesStreamProxy, rpcProfiler))
-                val serviceOutputStream = PrintStream(RemoteOutputStreamClient(serviceOutputStreamProxy, rpcProfiler))
-                checkedCompile(args, serviceOutputStream, rpcProfiler) {
-                    val res = body( compilerMessagesStream, rpcProfiler).code
-                    _lastUsedSeconds = nowSeconds()
-                    res
+                val compilerMessagesStream = PrintStream(BufferedOutputStream(RemoteOutputStreamClient(compilerMessagesStreamProxy, rpcProfiler), 4096))
+                val serviceOutputStream = PrintStream(BufferedOutputStream(RemoteOutputStreamClient(serviceOutputStreamProxy, rpcProfiler), 4096))
+                try {
+                    checkedCompile(args, serviceOutputStream, rpcProfiler) {
+                        val res = body(compilerMessagesStream, rpcProfiler).code
+                        _lastUsedSeconds = nowSeconds()
+                        res
+                    }
+                }
+                finally {
+                    serviceOutputStream.flush()
+                    compilerMessagesStream.flush()
                 }
             }
 
diff --git a/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/RemoteCompilationCanceledStatusClient.kt b/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/RemoteCompilationCanceledStatusClient.kt
index 056aa640b89..d3f9a430cb0 100644
--- a/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/RemoteCompilationCanceledStatusClient.kt
+++ b/compiler/rmi/rmi-server/src/org/jetbrains/kotlin/rmi/service/RemoteCompilationCanceledStatusClient.kt
@@ -20,10 +20,19 @@ import org.jetbrains.kotlin.progress.CompilationCanceledStatus
 import org.jetbrains.kotlin.rmi.CompilerCallbackServicesFacade
 import org.jetbrains.kotlin.rmi.DummyProfiler
 import org.jetbrains.kotlin.rmi.Profiler
+import java.util.concurrent.TimeUnit
 
+val CANCELED_STATUS_CHECK_THRESHOLD_NS = TimeUnit.MILLISECONDS.toNanos(100)
 
 class RemoteCompilationCanceledStatusClient(val facade: CompilerCallbackServicesFacade, val profiler: Profiler = DummyProfiler()): CompilationCanceledStatus {
+    @Volatile var lastChecked: Long = System.nanoTime()
     override fun checkCanceled() {
-        profiler.withMeasure(this) { facade.compilationCanceledStatus_checkCanceled() }
+        val curNanos = System.nanoTime()
+        if (curNanos - lastChecked > CANCELED_STATUS_CHECK_THRESHOLD_NS) {
+            profiler.withMeasure(this) {
+                facade.compilationCanceledStatus_checkCanceled()
+            }
+            lastChecked = curNanos
+        }
     }
 }