Linux KPTI performance hit on real workloads

There have been a lot of people quoting figures about the #Meltdown and #spectre issues on the internet. At hackers.mu, we decided to benchmark the latest patches in Linux kernel 4.11, on Void Linux. We use VoidLinux to avoid relying on systemd :)

Our spec machine:

CPU: Intel(R) Core(TM) i5–4460 CPU @ 3.20GHz (Haswell)

VoidLinux 4.14.11_1 #1 SMP PREEMPT Wed Jan 3 16:59:01 UTC 2018 x86_64 GNU/Linux

RAM: 32GB RAM

SSD: Samsung Evo 850 250GB

compiling linux kernel using make -j8.

Time taken:

real 30m59.314s
user 106m11.840s
sys 10m51.330s

Now with Linux kernel 4.11.8.

Kernel compilation:

real 29m13.027s
user 103m42.483s
sys 9m49.468s

Conclusion:

For kernel compilation, we are hitting a performance penalty of : 5%, with KPTI on my Intel haswell CPU.

[Feel free to submit difference ideas for benchmarking on Linux in the comments section]