It seems to me that we are OK with random as default behavior but we should print out the seed (and abstract it into a shared function across arches).
Happy to re-work the patch if my understanding is correct. Jun On Thu, May 18, 2023 at 6:09 AM Alex Bennée <alex.ben...@linaro.org> wrote: > > Peter Maydell <peter.mayd...@linaro.org> writes: > > > On Fri, 5 May 2023 at 01:23, Jun Sun <j...@junsun.net> wrote: > >> > >> Agree on the usefulness of generating the same test. That is the > >> reason behind adding --randseed option. Once a seed is set, it > >> always generates the same sequence of instructions. > >> > >> Basically with this patch, > >> > >> by default you will generate random instruction sequences for most > testing cases > >> you can provide a random seed option in the commandline to generate a > deterministic instruction sequence > >> > >> Without this patch, > >> > >> we always get one fixed sequence (ie. random seed == 0 case) > >> Otherwise we would have to manually modify code to generate random > >> instruction sequences or generate a different fixed sequence. > >> > >> Hope this clarifies things a little bit. > > > > Mmm; it comes down to: should we default to 'time' and > > require the user to specify --randseed 0 to get the old > > behaviour; or do we retain the current behaviour as the > > default and let the user pass an option if they want a > > non-reproducibly random output. > > > > Alex, what do you reckon? You probably have been using > > risugen more actively than me recently. I guess I vaguely > > lean to "default to randomize(time)". > > I'm easy either way as long as we as long as we print out the seed so we > can deterministically regenerate if we want to. > > > > > Also, should we make risugen print the random seed to stdout > > so you can repro it even if you didn't pass --randseed initially? > > > > Now that the random-seed-setting is 6 lines instead of 1, > > this should definitely be abstracted out to a function > > in the common code and not repeated in each per-arch file. > > > > thanks > > -- PMM > > > -- > Alex Bennée > Virtualisation Tech Lead @ Linaro >
