Two Year Ubuntu Linux Performance Comparison For Intel Xeon "Cascade Lake"
With this spring marking two years already since Intel introduced the 2nd Gen Xeon Scalable "Cascade Lake" processors plus with Ice Lake Xeon processors being on the horizon, here is a look at how the flagship Xeon Platinum 8280 2P performance has evolved atop open-source Linux during that duration. The benchmarks today are looking at the performance of Ubuntu 19.04 for that of roughly the shape the Linux performance/optimizations were at launch and then the performance today if moving to the in-development Ubuntu 21.04 and also shifting to the latest Linux 5.11 kernel and GCC 11 code compiler.
Out of curiosity and our benchmark passion, this article is looking at how the Intel Xeon Platinum 8280 2P Linux performance has evolved over the past two years. The software configurations tested were:
Ubuntu 19.04 - The Ubuntu 19.04 release as it shipped in April 2019 plus stable release updates, released the same month as the initial Cascade Lake processors. Ubuntu 19.04 rode the Linux 5.0 kernel, GCC 8.3 compiler, and other up-to-date components as of early 2019. Stable release updates have brought it roughly in line with the current security mitigations roughly where we are at today to avoid this article solely looking at mitigation overhead and not other upstream kernel improvements and performance optimizations.
Ubuntu 21.04 Dev - A daily snapshot of the in-development Ubuntu 21.04 ahead of its stable release in April. Ubuntu 21.04 is currently on the same Linux 5.8 kernel as Ubuntu 20.10, GCC 10.2.1, and other new components.
Ubuntu 21.04 Dev + Linux 5.11 - Ubuntu 21.04 prior to release will move to the new kernel series, which should end up being Linux 5.11 and is what is set to be released as stable upstream this weekend. So this run was Ubuntu 21.04 Dev upgraded to Linux 5.11 for the newest kernel experience.
Ubuntu 21.04 Dev + Linux 5.11 + GCC11 - Ubuntu 21.04 will be sticking to GCC 10 by default but this run is looking at the gcc-snapshot installation for showing how the Cascade Lake performance is looking for the GCC 11 compiler, which will be released as stable in the next month or two.
For all test runs, the CFLAGS/CXXFLAGS were set to "-O3 -march=native". Except where otherwise noted, each configuration was tested at its defaults/out-of-the-box configuration for the representative initial Linux experience, including the default security mitigations, P-State powersave being the Ubuntu default, etc.
The test profiles with the Phoronix Test Suite were obviously kept the same across the configurations as to just change the underlying operating system under test. The Intel Xeon Platinum 8280 2P processors continue to be tested with the Gigabyte S451-3R0 Storage Server. I've been using that Gigabyte 4U barebones server since Cascade Launch day and it has continued to prove very reliable and practical even with near-daily benchmark strain for about two years and still going strong.
As this comparison involved over 80 benchmarks, first up is a high level look at the results.
Indeed the new Ubuntu 21.04-based configurations yielded better performance than Ubuntu 19.04, as one would hope... Ubuntu 19.04 did still come in first place 10% of the time but that was often by very narrow margins. The launch stack of Ubuntu 19.04 came in last place 75% of the time as would be expected given the Linux/open-source progress over the past two years....
If taking the geometric mean of all 84 benchmarks conducted across the four configurations, the Xeon Platinum 8280 2P performance is up by about 7% overall with the bleeding-edge Ubuntu 21.04 on Linux 5.11 with GCC 11 compared to the initial state found with Ubuntu 19.04 two years ago. GCC 11 helped in some of the C/C++ benchmarks while much of that improvement was simply shifting to Ubuntu 21.04 itself. Linux 5.11 also didn't play much of a role in a majority of the benchmarks compared to Linux 5.8 given that the Intel Cascade Lake support has been quite mature for many kernel releases at this point and no major fundamental performance optimizations to note in recent kernels.