Re: [PATCH 1/1] test/ring: remove excessive inlining

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, May 10, 2022 at 11:23:53PM +0000, Honnappa Nagarahalli wrote:
> + Bruce, Stephen
> 
> <snip>
> 
> > 
> > Forcing inlining in test_ring_enqueue and test_ring_dequeue can cause the
> > compiled code to grow extensively when compiled with no optimization
> > (-O0 or -Og). This is default in the meson's debug configuration. This can collide
> > with compiler bugs and cause issues during linking of unit tests where the
> > api_type or esize are non-const variables causing inlining cascade. In perf tests
> > this is not the case in perf-tests as esize and api_type are const values.
> > 
> > One such case was discovered when porting DPDK to RISC-V. GCC 11.2 (and no
> > fix still in 12.1) is generating a short relative jump instruction (J <offset>) for
> > goto and for loops. When loop body grows extensively in ring test, the target
> > offset goes beyond supported offfset of +/- 1MB from PC. This is an obvious
> > bug in the GCC as RISC-V has a two-instruction construct to jump to any
> > absolute address (AUIPC+JALR).
> Is there a bug report created for this? Is it possible to add a link to the bug report?
> 
> > 
> > However there is no reason to force inlining as the test code works perfectly
> > fine without it.
> If this solves the problem, I prefer this as it is test code.
> 
+1 to this. I'm quite wary of changing the ring code itself.