mirror of
https://abf.rosa.ru/djam/kernel-5.15.git
synced 2025-02-23 04:42:47 +00:00
Pick fix of AMD CPU performance
This commit is contained in:
parent
6ccc5e5d4b
commit
9891da8dfc
2 changed files with 77 additions and 1 deletions
74
e400ad8b7e6a1b9102123c6240289a811501f7d9.patch
Normal file
74
e400ad8b7e6a1b9102123c6240289a811501f7d9.patch
Normal file
|
@ -0,0 +1,74 @@
|
|||
From e400ad8b7e6a1b9102123c6240289a811501f7d9 Mon Sep 17 00:00:00 2001
|
||||
From: Dave Hansen <dave.hansen@intel.com>
|
||||
Date: Thu, 22 Sep 2022 11:47:45 -0700
|
||||
Subject: [PATCH] ACPI: processor idle: Practically limit "Dummy wait"
|
||||
workaround to old Intel systems
|
||||
|
||||
Old, circa 2002 chipsets have a bug: they don't go idle when they are
|
||||
supposed to. So, a workaround was added to slow the CPU down and
|
||||
ensure that the CPU waits a bit for the chipset to actually go idle.
|
||||
This workaround is ancient and has been in place in some form since
|
||||
the original kernel ACPI implementation.
|
||||
|
||||
But, this workaround is very painful on modern systems. The "inl()"
|
||||
can take thousands of cycles (see Link: for some more detailed
|
||||
numbers and some fun kernel archaeology).
|
||||
|
||||
First and foremost, modern systems should not be using this code.
|
||||
Typical Intel systems have not used it in over a decade because it is
|
||||
horribly inferior to MWAIT-based idle.
|
||||
|
||||
Despite this, people do seem to be tripping over this workaround on
|
||||
AMD system today.
|
||||
|
||||
Limit the "dummy wait" workaround to Intel systems. Keep Modern AMD
|
||||
systems from tripping over the workaround. Remotely modern Intel
|
||||
systems use intel_idle instead of this code and will, in practice,
|
||||
remain unaffected by the dummy wait.
|
||||
|
||||
Reported-by: K Prateek Nayak <kprateek.nayak@amd.com>
|
||||
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
||||
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
|
||||
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
|
||||
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
|
||||
Link: https://lore.kernel.org/all/20220921063638.2489-1-kprateek.nayak@amd.com/
|
||||
Link: https://lkml.kernel.org/r/20220922184745.3252932-1-dave.hansen@intel.com
|
||||
---
|
||||
drivers/acpi/processor_idle.c | 23 ++++++++++++++++++++---
|
||||
1 file changed, 20 insertions(+), 3 deletions(-)
|
||||
|
||||
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
|
||||
index 16a1663d02d460..9f40917c49efbf 100644
|
||||
--- a/drivers/acpi/processor_idle.c
|
||||
+++ b/drivers/acpi/processor_idle.c
|
||||
@@ -531,10 +531,27 @@ static void wait_for_freeze(void)
|
||||
/* No delay is needed if we are in guest */
|
||||
if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
|
||||
return;
|
||||
+ /*
|
||||
+ * Modern (>=Nehalem) Intel systems use ACPI via intel_idle,
|
||||
+ * not this code. Assume that any Intel systems using this
|
||||
+ * are ancient and may need the dummy wait. This also assumes
|
||||
+ * that the motivating chipset issue was Intel-only.
|
||||
+ */
|
||||
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
|
||||
+ return;
|
||||
#endif
|
||||
- /* Dummy wait op - must do something useless after P_LVL2 read
|
||||
- because chipsets cannot guarantee that STPCLK# signal
|
||||
- gets asserted in time to freeze execution properly. */
|
||||
+ /*
|
||||
+ * Dummy wait op - must do something useless after P_LVL2 read
|
||||
+ * because chipsets cannot guarantee that STPCLK# signal gets
|
||||
+ * asserted in time to freeze execution properly
|
||||
+ *
|
||||
+ * This workaround has been in place since the original ACPI
|
||||
+ * implementation was merged, circa 2002.
|
||||
+ *
|
||||
+ * If a profile is pointing to this instruction, please first
|
||||
+ * consider moving your system to a more modern idle
|
||||
+ * mechanism.
|
||||
+ */
|
||||
inl(acpi_gbl_FADT.xpm_timer_block.address);
|
||||
}
|
||||
|
|
@ -32,7 +32,7 @@
|
|||
%define sublevel 72
|
||||
|
||||
# Release number. Increase this before a rebuild.
|
||||
%define rpmrel 1
|
||||
%define rpmrel 2
|
||||
%define fullrpmrel %{rpmrel}
|
||||
|
||||
%define rpmtag %{disttag}
|
||||
|
@ -308,6 +308,8 @@ Patch1: https://cdn.kernel.org/pub/linux/kernel/v%{kernelversion}.x/patch-%{kve
|
|||
# Patches from mainline
|
||||
# none
|
||||
Patch2: kernel-5.10.93-fix-perf-build.patch
|
||||
# https://www.opennet.ru/opennews/art.shtml?num=57838
|
||||
Patch3: https://github.com/torvalds/linux/commit/e400ad8b7e6a1b9102123c6240289a811501f7d9.patch
|
||||
|
||||
# ROSA-specific patches
|
||||
|
||||
|
|
Loading…
Add table
Reference in a new issue