On Sun, Dec 14, 2025 at 10:20:12AM -0600, Segher Boessenkool wrote:

Hi!

On Sun, Dec 14, 2025 at 06:32:44PM +0530, Mukesh Kumar Chaurasiya wrote:

quoted

| Test            | With Patch | Without Patch | % Change |
| --------------- | ---------- | ------------- | -------- |
| fork usec/op    | 833.986    | 814.809       | +2.35%   |

What causes this regression, did you investigate?  Maybe there is
something simple you can do to avoid this degradation :-)  All other
numbers look just fine :-)

Hey,

I ran this multiple times and took the average this time, below are the
results:
===========================================
Without patch
===========================================
╰─❯ perf bench syscall fork 
# Running 'syscall/fork' benchmark:
# Executed 10,000 fork() calls
     Total time: 8.514 [sec]

     851.415300 usecs/op
          1,174 ops/sec

╰─❯ perf bench syscall fork
# Running 'syscall/fork' benchmark:
# Executed 10,000 fork() calls
     Total time: 8.572 [sec]

     857.293600 usecs/op
          1,166 ops/sec

╰─❯ perf bench syscall fork 
# Running 'syscall/fork' benchmark:
# Executed 10,000 fork() calls
     Total time: 8.695 [sec]

     869.536500 usecs/op
          1,150 ops/sec
===========================================
With patch
===========================================
╰─❯ perf bench syscall fork 
# Running 'syscall/fork' benchmark:
# Executed 10,000 fork() calls
     Total time: 8.482 [sec]

     848.241300 usecs/op
          1,178 ops/sec

╰─❯ perf bench syscall fork 
# Running 'syscall/fork' benchmark:
# Executed 10,000 fork() calls
     Total time: 8.623 [sec]

     862.389000 usecs/op
          1,159 ops/sec

╰─❯ perf bench syscall fork 
# Running 'syscall/fork' benchmark:
# Executed 10,000 fork() calls
     Total time: 8.530 [sec]

     853.037200 usecs/op
          1,172 ops/sec
===========================================
Average:
===========================================
With Patch:
854.4964 usecs/op
1169 ops/sec

Without patch:
859.4151 usecs/op
1163 ops/sec

That's ~0.5% improvement when i take average through the runs.
This we can ignore as a standard deviation and consider that there are
no regression for these.

Regards,
Mukesh

quoted

| Test            | With Patch | Without Patch | % Change |
| --------------- | ---------- | ------------- | -------- |
| fork ops/sec    | 1,199      | 1,227         | -2.28%   |

(Same thing seen from another side)


Segher