Date: Tue, 2 Jun 2026 11:25:56 -0700 From: Adrian Chadd <adrian@freebsd.org> To: ShengYi Hung <aokblast@freebsd.org> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 7b26353a59d6 - main - hwpstate_intel: Disable package control on hybrid CPU Message-ID: <CAJ-Vmok7bt9hBpNta21QODhmXwKGhKFWWM5uTkNrdvTvANdRkw@mail.gmail.com> In-Reply-To: <6a1e7b3b.1a45a.91f6820@gitrepo.freebsd.org>
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.. it sounds like we want to split this up into package versus cluster frequency or something? What's the API look like right now? -adrian On Mon, 1 Jun 2026 at 23:42, ShengYi Hung <aokblast@freebsd.org> wrote: > > The branch main has been updated by aokblast: > > URL: https://cgit.FreeBSD.org/src/commit/?id=7b26353a59d66dc1bc611fd042a49b9e3bd13699 > > commit 7b26353a59d66dc1bc611fd042a49b9e3bd13699 > Author: ShengYi Hung <aokblast@FreeBSD.org> > AuthorDate: 2026-06-01 09:46:37 +0000 > Commit: ShengYi Hung <aokblast@FreeBSD.org> > CommitDate: 2026-06-02 06:41:41 +0000 > > hwpstate_intel: Disable package control on hybrid CPU > > In package control mode, the performance of all cores depends on the > most recent value written to the request field. If the last write comes > from an E-core, all cores are forced to align with the E-core > performance level, resulting in significant performance degradation. > Therefore, package control is disabled on hybrid-core systems. > > Reviewed by: olce > MFC after: 2 weeks > Sponsored by: The FreeBSD Foundation > Sponsored by: Framework Computer Inc > Differential Revision: https://reviews.freebsd.org/D57377 > --- > sys/x86/cpufreq/hwpstate_intel.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/sys/x86/cpufreq/hwpstate_intel.c b/sys/x86/cpufreq/hwpstate_intel.c > index 3d2cc0a5966b..db8600d7b89a 100644 > --- a/sys/x86/cpufreq/hwpstate_intel.c > +++ b/sys/x86/cpufreq/hwpstate_intel.c > @@ -321,9 +321,19 @@ out: > return (ret); > } > > +static void > +intel_hwpstate_hybrid_cb(void *ctx) > +{ > + uint32_t *small_cores = ctx; > + > + atomic_add_32(small_cores, PCPU_GET(small_core)); > +} > + > void > intel_hwpstate_identify(driver_t *driver, device_t parent) > { > + uint32_t small_cores = 0; > + > if (device_find_child(parent, "hwpstate_intel", DEVICE_UNIT_ANY) != NULL) > return; > > @@ -343,6 +353,17 @@ intel_hwpstate_identify(driver_t *driver, device_t parent) > if ((cpu_power_eax & CPUTPM1_HWP) == 0) > return; > > + /* > + * On hybrid-core systems, package-level control cannot be used. > + * It may cause all cores to run at the E-core frequency because > + * the resulting package frequency depends on the last core that > + * sets the frequency. > + */ > + smp_rendezvous_cpus(all_cpus, smp_no_rendezvous_barrier, > + intel_hwpstate_hybrid_cb, smp_no_rendezvous_barrier, &small_cores); > + if (small_cores > 0 && small_cores < mp_ncores) > + hwpstate_pkg_ctrl_enable = false; > + > if (BUS_ADD_CHILD(parent, 10, "hwpstate_intel", device_get_unit(parent)) > == NULL) > device_printf(parent, "hwpstate_intel: add child failed\n"); >home | help
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