Starting a process on M1(ARM) CPU is 10 times slower than on Intel CPU

[DanPristupov]

Description

I noticed that starting and running a process on M1 (ARM) CPU is 10 times slower than on Intel CPU.

Configuration

I made measures on MacOS on MBP16 Intel and MBP16 M1 Max (both are the latest available models at the moment).

I run /bin/ls as an example, but it can be any other process, for example /bin/date

using System.Diagnostics;
using System.Text;

Console.WriteLine("Start processes");
Run(16, "/bin/ls");

void Run(int count, string fileName)
{
    var stopWatch = Stopwatch.StartNew();
    for (var i = 0; i < count; i += 1)
    {
        RunProcess(fileName);
    }
    Console.WriteLine($"Total {stopWatch.Elapsed.TotalMilliseconds}");
}

void RunProcess(string fileName)
{
    var stopWatch = Stopwatch.StartNew();

    using (var process = new Process())
    {
        process.StartInfo = new ProcessStartInfo
        {
            FileName = fileName,
            UseShellExecute = false,
            RedirectStandardOutput = true,
            ErrorDialog = false,
            CreateNoWindow = true,
            RedirectStandardInput = true,
            StandardOutputEncoding = Encoding.UTF8,
        };

        process.Start();

        var output = process.StandardOutput.ReadToEnd();

        process.WaitForExit();
    }
    Console.WriteLine($"{fileName}: {stopWatch.Elapsed.TotalMilliseconds}");
}

Data

Intel (2.5 ms avg)

dotnet run --release
Start processes
/bin/ls: 25.0932
/bin/ls: 3.6286
/bin/ls: 3.565
/bin/ls: 3.6467
/bin/ls: 2.3761
/bin/ls: 2.3586
/bin/ls: 2.5641
/bin/ls: 2.4136
/bin/ls: 2.3298
/bin/ls: 2.2895
/bin/ls: 2.2861
/bin/ls: 2.274
/bin/ls: 2.2964
/bin/ls: 2.346
/bin/ls: 2.2755
/bin/ls: 2.3004
Total 65.3108
Done!

M1 (25ms avg)

dotnet run --release
Start processes
/bin/ls: 100.2816
/bin/ls: 26.076
/bin/ls: 21.451
/bin/ls: 23.9278
/bin/ls: 21.1879
/bin/ls: 24.8415
/bin/ls: 25.9347
/bin/ls: 22.8774
/bin/ls: 42.4205
/bin/ls: 21.7012
/bin/ls: 23.1033
/bin/ls: 23.0439
/bin/ls: 20.8563
/bin/ls: 21.0834
/bin/ls: 20.9084
/bin/ls: 25.0697
Total 468.7015
Done!

P.S. You might be interested in seeing the roots of that issue: #67506

[ghost]

Tagging subscribers to this area: @dotnet/area-system-diagnostics-process
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

I noticed that starting and running a process on M1 (ARM) CPU is 10 times slower than on Intel CPU.

Configuration

I made measures on MacOS on MBP16 Intel and MBP16 M1 Max (both are the latest available models at the moment).

I run /bin/ls as an example, but it can be any other process, for example /bin/date

using System.Diagnostics;
using System.Text;

Console.WriteLine("Start processes");
Run(16, "/bin/ls");

void Run(int count, string fileName)
{
    var stopWatch = Stopwatch.StartNew();
    for (var i = 0; i < count; i += 1)
    {
        RunProcess(fileName);
    }
    Console.WriteLine($"Total {stopWatch.Elapsed.TotalMilliseconds}");
}

void RunProcess(string fileName)
{
    var stopWatch = Stopwatch.StartNew();

    using (var process = new Process())
    {
        process.StartInfo = new ProcessStartInfo
        {
            FileName = fileName,
            UseShellExecute = false,
            RedirectStandardOutput = true,
            ErrorDialog = false,
            CreateNoWindow = true,
            RedirectStandardInput = true,
            StandardOutputEncoding = Encoding.UTF8,
        };

        process.Start();

        var output = process.StandardOutput.ReadToEnd();

        process.WaitForExit();
    }
    Console.WriteLine($"{fileName}: {stopWatch.Elapsed.TotalMilliseconds}");
}

Data

Intel (2.5 ms avg)

dotnet run --release
Start processes
/bin/ls: 25.0932
/bin/ls: 3.6286
/bin/ls: 3.565
/bin/ls: 3.6467
/bin/ls: 2.3761
/bin/ls: 2.3586
/bin/ls: 2.5641
/bin/ls: 2.4136
/bin/ls: 2.3298
/bin/ls: 2.2895
/bin/ls: 2.2861
/bin/ls: 2.274
/bin/ls: 2.2964
/bin/ls: 2.346
/bin/ls: 2.2755
/bin/ls: 2.3004
Total 65.3108
Done!

M1 (25ms avg)

dotnet run --release
Start processes
/bin/ls: 100.2816
/bin/ls: 26.076
/bin/ls: 21.451
/bin/ls: 23.9278
/bin/ls: 21.1879
/bin/ls: 24.8415
/bin/ls: 25.9347
/bin/ls: 22.8774
/bin/ls: 42.4205
/bin/ls: 21.7012
/bin/ls: 23.1033
/bin/ls: 23.0439
/bin/ls: 20.8563
/bin/ls: 21.0834
/bin/ls: 20.9084
/bin/ls: 25.0697
Total 468.7015
Done!

P.S. You might be interested in seeing the roots of that issue: #67506

Author:	DanPristupov
Assignees:	-
Labels:	area-System.Diagnostics.Process, tenet-performance, untriaged
Milestone:	-

[stephentoub]

I assume you don't see such a difference if you just run the commands from the shell and time how long they take to invoke?

[EgorBo]

Seems like it got better in .NET 7.0:

(at least for x64)

[DanPristupov]

@EgorBo may be I'm missing something, but the 'Apple M1 Max' processor on your screenshot is marked as 'Same'.

[EgorBo]

Sorry I didn't notice you were talking about M1 specifically

[adamsitnik]

@DanPristupov can you observe the same difference if you run these commands from shell?

[DanPristupov]

@adamsitnik

Intel (3ms):

time ls
ls  0.00s user 0.00s system 80% cpu 0.003 total

M1 (4ms):

time ls
ls  0.00s user 0.00s system 49% cpu 0.004 total

Is that what you ask?