RE: [PATCH 4/7] app/test/mempool_perf: drop constant-values replay

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Andrew Rybchenko [mailto:andrew.rybchenko@oktetlabs.ru]
> Sent: Monday, 1 June 2026 10.35
> 
> On 5/29/26 8:10 PM, Stephen Hemminger wrote:
> > The second nested matrix replays each (n_get_bulk == n_put_bulk)
> > point with use_constant_values=1 to exercise the compile-time
> > constant bulk-size paths in test_loop().  This roughly doubles the
> > work for the get/put diagonal at every n_keep without adding new
> > signal: the cycles/op result for a constant bulk is interesting in
> > isolated inlining studies, not in routine regression sweeps.
> >
> > Drop the replay.  The use_constant_values switch and its branches
> > in test_loop() are retained for now since they are exercised by
> > hand in any local benchmarking.
> >
> > Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> 
> As far as I can see you delete the only place where use_constant_values
> is set to 1. It looks suspicious and basically preserves dead code.
> Since Morten added the code, the patch should wait for his approval.

Having used the mempool perf test extensively myself, I agree that it is painfully slow.
Mempools are very often used with constant request sizes, so testing their performance remains relevant for regression sweeps too.
NAK to this change.

Maybe the testing of constant values could be reduced by using a subset of the non-constant mix of values.

> 
> > ---
> >   app/test/test_mempool_perf.c | 8 --------
> >   1 file changed, 8 deletions(-)
> >
> > diff --git a/app/test/test_mempool_perf.c
> b/app/test/test_mempool_perf.c
> > index 19591ad0c9..dd2f0bbaca 100644
> > --- a/app/test/test_mempool_perf.c
> > +++ b/app/test/test_mempool_perf.c
> > @@ -423,14 +423,6 @@ do_one_mempool_test(struct rte_mempool *mp,
> unsigned int cores, int external_cac
> >   				ret = launch_cores(mp, cores);
> >   				if (ret < 0)
> >   					return -1;
> > -
> > -				/* replay test with constant values */
> > -				if (n_get_bulk == n_put_bulk) {
> > -					use_constant_values = 1;
> > -					ret = launch_cores(mp, cores);
> > -					if (ret < 0)
> > -						return -1;
> > -				}
> >   			}
> >   		}
> >   	}