From: Christian Loehle <christian.loehle@arm.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>,
linux-pm <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Subject: [PATCH] Revert "intel_idle: Rescan "dead" SMT siblings during, initialization"
Date: Thu, 28 Aug 2025 15:25:58 +0100 [thread overview]
Message-ID: <724616a2-6374-4ba3-8ce3-ea9c45e2ae3b@arm.com> (raw)
This reverts commit a430c11f401589a0f4f57fd398271a5d85142c7a.
Calling arch_cpu_rescan_dead_smt_siblings() in intel_idle_init with
boot parameter nosmt and maxcpus active hotplugged boot-offline CPUs
in (and leave them online) which weren't supposed to be online.
With the revert and nosmt and maxcpus=12 on a raptor lake:
cpu online capacity
cpu0 1 1009
cpu1 0 -
cpu2 1 1009
cpu3 0 -
cpu4 1 1009
cpu5 0 -
cpu6 1 1009
cpu7 0 -
cpu8 1 1024
cpu9 0 -
cpu10 1 1024
cpu11 0 -
cpu12 1 1009
cpu13 0 -
cpu14 1 1009
cpu15 0 -
cpu16 1 623
cpu17 1 623
cpu18 1 623
cpu19 1 623
cpu20 0 -
cpu21 0 -
cpu22 0 -
cpu23 0 -
Previously:
cpu online capacity
cpu0 1 1009
cpu1 0 -
cpu2 1 1009
cpu3 0 -
cpu4 1 1009
cpu5 0 -
cpu6 1 1009
cpu7 0 -
cpu8 1 1024
cpu9 0 -
cpu10 1 1024
cpu11 0 -
cpu12 1 1009
cpu13 0 -
cpu14 1 1009
cpu15 0 -
cpu16 1 623
cpu17 1 623
cpu18 1 623
cpu19 1 623
cpu20 1 623
cpu21 1 623
cpu22 1 623
cpu23 1 623
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
---
Rafael, I don't immediately see how to fix this properly so I won't
try to, feel free to treat this as a bug report.
drivers/idle/intel_idle.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 91a7b7e7c0c8..a9c58395a425 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -2507,8 +2507,6 @@ static int __init intel_idle_init(void)
pr_debug("Local APIC timer is reliable in %s\n",
boot_cpu_has(X86_FEATURE_ARAT) ? "all C-states" : "C1");
- arch_cpu_rescan_dead_smt_siblings();
-
return 0;
hp_setup_fail:
--
2.34.1
next reply other threads:[~2025-08-28 14:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-28 14:25 Christian Loehle [this message]
2025-08-28 14:44 ` Rafael J. Wysocki
2025-08-28 16:13 ` Rafael J. Wysocki
2025-08-28 19:06 ` Rafael J. Wysocki
2025-08-28 21:44 ` Christian Loehle
2025-08-29 17:49 ` Rafael J. Wysocki
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