Use an auto-incremented id instead of guid.

Always use same ProgramName regardless of --keepFiles.
Include benchmark assembly name in ProgramName.

src/BenchmarkDotNet/Running/BuildPartition.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Reflection;
+using System.Threading;
 using BenchmarkDotNet.Characteristics;
 using BenchmarkDotNet.Configs;
 using BenchmarkDotNet.Environments;
@@ -18,15 +19,20 @@ namespace BenchmarkDotNet.Running
 {
     public class BuildPartition
     {
+        // We use an auto-increment global counter instead of Guid to guarantee uniqueness per benchmark run (Guid has a small chance to collide),
+        // assuming there are fewer than 4 billion build partitions (a safe assumption).
+        private static int s_partitionCounter;
+
         public BuildPartition(BenchmarkBuildInfo[] benchmarks, IResolver resolver)
         {
             Resolver = resolver;
             RepresentativeBenchmarkCase = benchmarks[0].BenchmarkCase;
             Benchmarks = benchmarks;
-            var keepBenchmarkFiles = benchmarks[0].Config.Options.IsSet(ConfigOptions.KeepBenchmarkFiles);
-            var guid = Guid.NewGuid().ToString();
-            ProgramName = keepBenchmarkFiles ? RepresentativeBenchmarkCase.Job.FolderInfo : guid;
-            ProgramDirectory = keepBenchmarkFiles ? Path.Combine(RepresentativeBenchmarkCase.Job.FolderInfo, guid) : guid;
+            // Combine the benchmark's assembly name, folder info, and build partition id.
+            string benchmarkAssemblyName = RepresentativeBenchmarkCase.Descriptor.Type.Assembly.GetName().Name;
+            string folderInfo = RepresentativeBenchmarkCase.Job.FolderInfo;
+            int id = Interlocked.Increment(ref s_partitionCounter);
+            ProgramName = $"{benchmarkAssemblyName}-{folderInfo}-{id}";
             LogBuildOutput = benchmarks[0].Config.Options.IsSet(ConfigOptions.LogBuildOutput);
             GenerateMSBuildBinLog = benchmarks[0].Config.Options.IsSet(ConfigOptions.GenerateMSBuildBinLog);
         }
@@ -35,8 +41,6 @@ public BuildPartition(BenchmarkBuildInfo[] benchmarks, IResolver resolver)
 
         public string ProgramName { get; }
 
-        public string ProgramDirectory { get; }
-
         /// <summary>
         /// the benchmarks are grouped by the build settings
         /// so you can use this benchmark to get the runtime settings

src/BenchmarkDotNet/Toolchains/DotNetCli/DotNetCliGenerator.cs

@@ -36,19 +36,19 @@ protected DotNetCliGenerator(string targetFrameworkMoniker, string cliPath, stri
         /// we are limited by xprojs (by default compiles all .cs files in all subfolders, Program.cs could be doubled and fail the build)
         /// and also by NuGet internal implementation like looking for global.json file in parent folders
         /// </summary>
-        protected override string GetBuildArtifactsDirectoryPath(BuildPartition buildPartition, string programDirectory)
+        protected override string GetBuildArtifactsDirectoryPath(BuildPartition buildPartition, string programName)
         {
             if (GetSolutionRootDirectory(out var directoryInfo))
             {
-                return Path.Combine(directoryInfo.FullName, programDirectory);
+                return Path.Combine(directoryInfo.FullName, programName);
             }
 
             // we did not find global.json or any Visual Studio solution file?
             // let's return it in the old way and hope that it works ;)
             var parent = new DirectoryInfo(Directory.GetCurrentDirectory()).Parent;
             if (parent == null)
                 throw new DirectoryNotFoundException("Parent directory for current directory");
-            return Path.Combine(parent.FullName, programDirectory);
+            return Path.Combine(parent.FullName, programName);
         }
 
         internal static bool GetSolutionRootDirectory(out DirectoryInfo directoryInfo)

src/BenchmarkDotNet/Toolchains/GeneratorBase.cs

@@ -42,7 +42,7 @@ public GenerateResult GenerateProject(BuildPartition buildPartition, ILogger log
         /// <summary>
         /// returns a path to the folder where auto-generated project and code are going to be placed
         /// </summary>
-        [PublicAPI] protected abstract string GetBuildArtifactsDirectoryPath(BuildPartition assemblyLocation, string programDirectory);
+        [PublicAPI] protected abstract string GetBuildArtifactsDirectoryPath(BuildPartition assemblyLocation, string programName);
 
         /// <summary>
         /// returns a path where executable should be found after the build (usually \bin)
@@ -128,10 +128,10 @@ private ArtifactsPaths GetArtifactsPaths(BuildPartition buildPartition, string r
             // its not ".cs" in order to avoid VS from displaying and compiling it with xprojs/csprojs that include all *.cs by default
             const string codeFileExtension = ".notcs";
 
-            string buildArtifactsDirectoryPath = GetBuildArtifactsDirectoryPath(buildPartition, buildPartition.ProgramDirectory);
+            string programName = buildPartition.ProgramName;
+            string buildArtifactsDirectoryPath = GetBuildArtifactsDirectoryPath(buildPartition, programName);
             string binariesDirectoryPath = GetBinariesDirectoryPath(buildArtifactsDirectoryPath, buildPartition.BuildConfiguration);
 
-            string programName = buildPartition.ProgramName;
             string executablePath = GetExecutablePath(binariesDirectoryPath, programName);
 
             return new ArtifactsPaths(

src/BenchmarkDotNet/Toolchains/NativeAot/Generator.cs

@@ -61,10 +61,10 @@ internal Generator(string ilCompilerVersion,
 
         protected override string GetExecutableExtension() => OsDetector.ExecutableExtension;
 
-        protected override string GetBuildArtifactsDirectoryPath(BuildPartition buildPartition, string programDirectory)
+        protected override string GetBuildArtifactsDirectoryPath(BuildPartition buildPartition, string programName)
             => useTempFolderForRestore
-                ? Path.Combine(Path.GetTempPath(), programDirectory) // store everything in temp to avoid collisions with IDE
-                : base.GetBuildArtifactsDirectoryPath(buildPartition, programDirectory);
+                ? Path.Combine(Path.GetTempPath(), programName) // store everything in temp to avoid collisions with IDE
+                : base.GetBuildArtifactsDirectoryPath(buildPartition, programName);
 
         protected override string GetBinariesDirectoryPath(string buildArtifactsDirectoryPath, string configuration)
             => Path.Combine(buildArtifactsDirectoryPath, "bin", configuration, TargetFrameworkMoniker, runtimeIdentifier, "publish");

src/BenchmarkDotNet/Toolchains/Roslyn/Generator.cs

@@ -13,7 +13,7 @@ namespace BenchmarkDotNet.Toolchains.Roslyn
     [PublicAPI]
     public class Generator : GeneratorBase
     {
-        protected override string GetBuildArtifactsDirectoryPath(BuildPartition buildPartition, string programDirectory)
+        protected override string GetBuildArtifactsDirectoryPath(BuildPartition buildPartition, string programName)
             => Path.GetDirectoryName(buildPartition.AssemblyLocation);
 
         [PublicAPI]

tests/BenchmarkDotNet.Tests/CsProjGeneratorTests.cs

@@ -220,9 +220,9 @@ public void TestAssemblyFilePathIsUsedWhenTheAssemblyLocationIsNotEmpty()
 
         private class SteamLoadedBuildPartition : CsProjGenerator
         {
-            internal string ResolvePathForBinaries(BuildPartition buildPartition, string programDirectory)
+            internal string ResolvePathForBinaries(BuildPartition buildPartition, string programName)
             {
-                return base.GetBuildArtifactsDirectoryPath(buildPartition, programDirectory);
+                return base.GetBuildArtifactsDirectoryPath(buildPartition, programName);
             }
 
             public SteamLoadedBuildPartition(string targetFrameworkMoniker, string cliPath, string packagesPath, string runtimeFrameworkVersion, bool isNetCore)