git: 7b26353a59d6 - main - hwpstate_intel: Disable package control on hybrid CPU

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");