Messages in this thread | | | Subject | Re: [PATCH 2/2] x86: fix platform info detection in frequency invariance | From | Giovanni Gherdovich <> | Date | Mon, 23 May 2022 11:56:00 +0200 |
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On Fri, 2022-05-20 at 09:44 -0700, Dave Hansen wrote: > On 5/20/22 09:10, Giovanni Gherdovich wrote: > > if (slv_set_max_freq_ratio(&base_freq, &turbo_freq)) > > goto out; > > > > - if (x86_match_cpu(has_glm_turbo_ratio_limits) && > > - skx_set_max_freq_ratio(&base_freq, &turbo_freq, 1)) > > + if (x86_match_cpu(has_glm_turbo_ratio_limits)) { > > + skx_set_max_freq_ratio(&base_freq, &turbo_freq, 1); > > goto out; > > + } > > > > - if (x86_match_cpu(has_knl_turbo_ratio_limits) && > > - knl_set_max_freq_ratio(&base_freq, &turbo_freq, 1)) > > + if (x86_match_cpu(has_knl_turbo_ratio_limits)) { > > + knl_set_max_freq_ratio(&base_freq, &turbo_freq, 1); > > goto out; > > + } > > > > - if (x86_match_cpu(has_skx_turbo_ratio_limits) && > > - skx_set_max_freq_ratio(&base_freq, &turbo_freq, 4)) > > + if (x86_match_cpu(has_skx_turbo_ratio_limits)) { > > + skx_set_max_freq_ratio(&base_freq, &turbo_freq, 4); > > goto out; > > + } > > > > if (core_set_max_freq_ratio(&base_freq, &turbo_freq)) > > goto out; > > But didn't the last patch in the series carefully change the return > value for knl_set_max_freq_ratio()? Now, the only call site is ignoring > the return value? That seems odd.
Thanks for having a look! You're right. I need to either check these return values, or not have them at all.
> > Also, this is a mess. These constructs: > > static const struct x86_cpu_id has_knl_turbo_ratio_limits[] = { > X86_MATCH(XEON_PHI_KNL), > X86_MATCH(XEON_PHI_KNM), > {} > }; > > static const struct x86_cpu_id has_skx_turbo_ratio_limits[] = { > X86_MATCH(SKYLAKE_X), > {} > }; > > static const struct x86_cpu_id has_glm_turbo_ratio_limits[] = { > X86_MATCH(ATOM_GOLDMONT), > X86_MATCH(ATOM_GOLDMONT_D), > X86_MATCH(ATOM_GOLDMONT_PLUS), > {} > }; > > are rather goofy. A single array like rapl_ids[] that points to the > handler function would do us a lot more good here, say: > > static const struct x86_cpu_id has_knl_turbo_ratio_limits[] = { > X86_MATCH(XEON_PHI_KNL, &knl_set_max_freq_ratio), > X86_MATCH(XEON_PHI_KNM, &knl_set_max_freq_ratio), > X86_MATCH(SKYLAKE_X, &skx_set_max_freq_ratio), > X86_MATCH(ATOM_GOLDMONT, &skx_set_max_freq_ratio), > X86_MATCH(ATOM_GOLDMONT_D, &skx_set_max_freq_ratio), > X86_MATCH(ATOM_GOLDMONT_PLUS, &skx_set_max_freq_ratio), > X86_MATCH(ANY, &core_set_max_freq_ratio), > {} > }; > > That would get rid of all the goofy gotos and actually puts all the > logic in one place. BTW, I'm not 100% sure about the 'ANY' line. I > think that's how those work, but please double-check me on it.
That's good advice. I'll do that consolidation.
> > While it's generally best to keep bug fixes to a minimum, I think this > one is worth a bit of a cleanup because it will remove a bunch of spaghetti.
Thanks, Giovanni
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