Originally posted by CochainComplex
View Post
Benchmarking The Linux Kernel With An "-O3" Optimized Build
Collapse
X
-
Originally posted by V1tol View PostI think having -march=native gives more performance gains, than -O2 => -O3 transition.
Comment
-
-
Originally posted by milkylainen View PostI think the results should be interpreted otherwise.
It's not strange that you don't see any benefits from something that spends < 1% cpu time in kernelspace.
If you're measuring an entire system then yeah, perhaps not that much difference.
But as the synthetic tests measuring syscalls or actual kernel operations (like context switching)...
Then wow did that O3 flag mean improvement!
In summary: It's unfair to say that it doesn't help the kernel when measuring an entire system.
It gives such a big improvement that I suspect that it involves some bugs.
For example, maybe it somehow removes the flushing/software migration for spectre/meltdown?
Comment
-
-
Originally posted by NobodyXu View Post
I speculate the result of context switching might be wrong.
It gives such a big improvement that I suspect that it involves some bugs.
For example, maybe it somehow removes the flushing/software migration for spectre/meltdown?
Comment
-
-
Originally posted by milkylainen View PostI think the results should be interpreted otherwise.
It's not strange that you don't see any benefits from something that spends < 1% cpu time in kernelspace.
If you're measuring an entire system then yeah, perhaps not that much difference.
But as the synthetic tests measuring syscalls or actual kernel operations (like context switching)...
Then wow did that O3 flag mean improvement!
In summary: It's unfair to say that it doesn't help the kernel when measuring an entire system.
Comment
-
-
When it came to the -O3 kernel build for other workloads like gaming/graphics, web browsing performance, and various creator workloads there was no measurable benefit from the -O3 kernel.
Case closed.
Comment
-
-
Originally posted by birdie View Post
Just what I expected. A well written kernel must have next to zero impact on performance other than using the CPU intensive features the kernel itself provides, i.e. encryption, connections, context-switching, etc. which is not absolute most users ever deal with.
Case closed.
Comment
-
Comment