Re: [PATCH bpf-next] bpf: abstract loop unrolling pragmas in BPF selftests

[Eduard Zingerman <eddyz87@gmail.com>]

On Thu, 2024-02-08 at 16:35 +0100, Jose E. Marchesi wrote:
[...]

> If the compiler generates assembly code the same code for profile2.c for
> before and after, that means that the loop does _not_ get unrolled when
> profiler.inc.h is built with -O2 but without #pragma unroll.
> 
> But what if #pragma unroll is used?  If it unrolls then, that would mean
> that the pragma does something more than -funroll-loops/-O2.
> 
> Sorry if I am not making sense.  Stuff like this confuses me to no end
> ;)

Sorry, I messed up while switching branches :(
Here are the correct stats:

| File            | insn # | insn # |
|                 | before |  after |
|-----------------+--------+--------|
| profiler1.bpf.o |  16716 |   4813 |
| profiler2.bpf.o |   2088 |   2050 |
| profiler3.bpf.o |   4465 |   1690 |