About the Python Speed Center
The Python Speed Center is the public performance dashboard for CPython. Every night it builds the current development branch and the maintenance branches from source, runs the pyperformance benchmark suite on dedicated hardware, and records the results here so that anyone can see how the interpreter's speed changes commit by commit.
Executables and machines
On this site an executable is a particular way of building CPython and an environment is the machine it ran on. The names below are the ones that can be selected in the sidebars.
| Environment | Machine | Results |
|---|---|---|
speed-python |
x86-64: HP ProLiant DL380 G7 at OSUOSL | October 2021 to present |
ampere-one |
AArch64: Ampere One server hosted by Arm | August 2025 to present |
arm-neoverse |
AArch64: the previous Arm Neoverse machine, replaced by
ampere-one |
May 2023 to August 2025 |
bb-benchmark-machine |
A separate, short-lived benchmark worker | October 2021 to March 2023 |
speed-python-historical |
Results from before the current speed-python
environment was set up, kept for reference |
November 2020 to October 2021 |
Retired environments no longer receive results but are kept so that old data stays reachable through the Timeline and Comparison pages.
The x86-64 machine (speed-python)
Nicknamed "the beast", this server was donated to the Python Software Foundation by the HP Open Source Program Office in 2011. The acquisition was announced on Jesse Noller's blog.
- HP ProLiant DL380 G7 (2U)
- 2× Intel Xeon X5680, 3.33 GHz, 6 cores each, 12 MB cache
- 16 GB RAM (4× 4 GB DDR3-1333 registered, dual rank)
- 4× 300 GB 15k rpm SAS drives on an HP Smart Array P410i controller with 1 GB flash-backed write cache, hardware RAID with a simple LVM layout
- Dual HP NC382i dual-port gigabit adapters, redundant 750 W power supplies, iLO Advanced
- Ubuntu 18.04 LTS
Racking, hardware administration and all bandwidth are donated by the Oregon State University Open Source Lab (OSUOSL), long-standing supporters of open source and of the PSF. We are very grateful to both HP and OSUOSL.
The AArch64 machine (ampere-one)
This server was donated to the PSF by Arm Ltd, who also host it.
- Ampere One, 192 cores, 64-bit Armv8.6+, 3.6 GHz
- Per core: 2 MB L2, 16 KB L1 instruction cache, 64 KB L1 data cache
- 512 GB RAM (8× 64 GB DDR5-5200 registered)
- 1.7 TB and 3.5 TB NVMe drives
- 2× 10 Gbps networking
- Ubuntu 24.04 LTS, managed through the PSF Salt infrastructure; Diego Russo has serial console access
We cannot thank Arm enough for the hardware, the hosting and the administration.
History
The Speed Center started as a shared project between the CPython, PyPy,
IronPython and Jython teams. At the PyCon 2011 VM and language summits the
maintainers of the major implementations agreed to move to a common benchmark
suite and a single performance-oriented site, modelled on the PyPy team's
speed.pypy.org and using the Codespeed software they had adopted. HP donated
the first machine the same year. Today the site focuses on CPython, results
for PyPy can be found on speed.pypy.org.
Software
This site runs on Codespeed,
a Django application for tracking and analysing the performance of a code
base over time. The Speed Center's own fork, including the templates and
styling you are looking at, is maintained at
python/codespeed,
currently at commit d84c6dfc8bca.
Contact
Questions, problems and suggestions about this site are welcome in the Core Development category on discuss.python.org. Problems with the site's code can be reported on the python/codespeed issue tracker, and problems with the benchmarks themselves on the pyperformance tracker.