New GitHub issue #118749 from Venkat2811:<br>
<hr>
<pre>
# Bug report
### Bug description:
Hello Team,
Thanks for the great work so far and recent nogil efforts. I wanted to explore performance of asyncio with [CPU-GPU bound multi-threading ](https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.loop.run_in_executor) in nogil setup. So, started with simple benchmark as seen below:
```python
import sys
from concurrent.futures import ThreadPoolExecutor
def fib(n):
if n < 2: return 1
return fib(n-1) + fib(n-2)
threads = 8
if len(sys.argv) > 1:
threads = int(sys.argv[1])
with ThreadPoolExecutor(max_workers=threads) as executor:
for _ in range(threads):
executor.submit(lambda: print(fib(34)))
```
[Original Source](https://github.com/colesbury/nogil?tab=readme-ov-file#example)
**Results:**
- python 3.13.a06 with gil:
htop shows 2 running tasks, and only one core is utilized for 100%
```bash
$ time /usr/bin/python3.13 fib.py
9227465
9227465
9227465
9227465
9227465
9227465
9227465
9227465
/usr/bin/python3.13 fib.py 6,46s user 0,04s system 100% cpu 6,447 total
```
- `libpython3.13-nogil amd64 3.13.0~a6-1+jammy2` [source](https://launchpad.net/~deadsnakes/+archive/ubuntu/ppa/+packages) nogil:
htop shows 9 running tasks, and 8 cores close to 100% utilization, but slower.
```bash
$ time /usr/bin/python3.13-nogil -X gil=0 fib.py
9227465
9227465
9227465
9227465
9227465
9227465
9227465
9227465
/usr/bin/python3.13-nogil -X gil=0 fib.py 168,81s user 0,06s system 788% cpu 21,410 total
```
My CPU: `AMD Ryzen 7 5800X 8-Core Processor`
OS: `Ubuntu 22.04.4 LTS`
So looks like there is overhead when using multiple cores. Is this expected with this version ? Are results similar with Intel & M1 CPUs as well ?
Results documented [here](https://github.com/colesbury/nogil?tab=readme-ov-file#example) in version `3.9.12` on Intel is better.
### CPython versions tested on:
3.13
### Operating systems tested on:
Linux
</pre>
<hr>
<a href="https://github.com/python/cpython/issues/118749">View on GitHub</a>
<p>Labels: type-bug</p>
<p>Assignee: </p>