diff --git a/chibild/chibild.core/CilLinker.cs b/chibild/chibild.core/CilLinker.cs
index 14cedb4..f160445 100644
--- a/chibild/chibild.core/CilLinker.cs
+++ b/chibild/chibild.core/CilLinker.cs
@@ -157,11 +157,8 @@ when Path.GetExtension(relativePath) == ".a":
                             this.logger,
                             baseInputPath,
                             relativePath,
-                            // Create this assembly specific resolver,
-                            // because shared resolver can not resolve on multi-threaded context.
-                            // At the cost of having to load it again later in the primary assembly resolver.
                             this.CreateAssemblyResolver(
-                                ReadingMode.Immediate,
+                                ReadingMode.Deferred,
                                 assemblyReferenceBasePaths)),
                     };
                     break;
@@ -194,11 +191,8 @@ when Path.GetExtension(relativePath) == ".a":
                                 this.logger,
                                 foundEntry.basePath,
                                 foundEntry.fileName,
-                                // Create this assembly specific resolver,
-                                // because shared resolver can not resolve on multi-threaded context.
-                                // At the cost of having to load it again later in the primary assembly resolver.
                                 this.CreateAssemblyResolver(
-                                    ReadingMode.Immediate,
+                                    ReadingMode.Deferred,
                                     assemblyReferenceBasePaths)),
                         };
                     }
diff --git a/chibild/chibild.core/Internal/MultipleSymbolReaderProvider.cs b/chibild/chibild.core/Internal/MultipleSymbolReaderProvider.cs
index 096e03a..949d3f2 100644
--- a/chibild/chibild.core/Internal/MultipleSymbolReaderProvider.cs
+++ b/chibild/chibild.core/Internal/MultipleSymbolReaderProvider.cs
@@ -8,6 +8,7 @@
 /////////////////////////////////////////////////////////////////////////////////////
 
 using chibicc.toolchain.Internal;
+using chibicc.toolchain.IO;
 using chibicc.toolchain.Logging;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
@@ -53,17 +54,16 @@ public MultipleSymbolReaderProvider(ILogger logger) =>
             if (File.Exists(path))
             {
                 var ms = new MemoryStream();
-                using (var mdbStream = new FileStream(
-                    path, FileMode.Open, FileAccess.Read, FileShare.Read))
+                using (var stream = StreamUtilities.OpenStream(path, false))
                 {
-                    mdbStream.CopyTo(ms);
+                    stream.CopyTo(ms);
                 }
                 ms.Position = 0;
 
                 var sr = provider.GetSymbolReader(module, ms);
                 if (this.loaded.Add(path))
                 {
-                    this.logger.Debug($"Symbol loaded from: {path}");
+                    this.logger.Debug($"Debug symbol is loaded from: {path}");
                 }
                 
                 return sr;
@@ -98,7 +98,7 @@ public MultipleSymbolReaderProvider(ILogger logger) =>
                             var sr = embeddedProvider.GetSymbolReader(module, fullPath);
                             if (this.loaded.Add(fullPath))
                             {
-                                this.logger.Debug($"Embedded symbol loaded from: {fullPath}");
+                                this.logger.Debug($"Embedded debug symbol is loaded from: {fullPath}");
                             }
 
                             return sr;
@@ -119,7 +119,7 @@ public MultipleSymbolReaderProvider(ILogger logger) =>
 
                     if (this.notFound.Add(fileName))
                     {
-                        this.logger.Trace($"Symbol not found: {fileName}");
+                        this.logger.Trace($"Debug symbol is not found: {fileName}");
                     }
                 }
             }
diff --git a/toolchain.common/IO/StreamUtilities.cs b/toolchain.common/IO/StreamUtilities.cs
index a6ed0e6..2d48faa 100644
--- a/toolchain.common/IO/StreamUtilities.cs
+++ b/toolchain.common/IO/StreamUtilities.cs
@@ -21,5 +21,6 @@ public static Stream OpenStream(string path, bool writable) =>
                 path,
                 writable ? FileMode.Create : FileMode.Open,
                 writable ? FileAccess.ReadWrite : FileAccess.Read,
-                FileShare.Read);
+                FileShare.Read,
+                1024 * 1024);
 }