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x86-tsc-sched-recompute-cyc2ns_offset-s-during-resume-from-sleep-states.patch 

Fix load balancing after suspend/resume cycle (taken from 2.6.32 stable queue)
This commit is contained in:
Chuck Ebbert 2010-09-05 06:07:58 -04:00
parent c22521011c
commit fb84bd51fb
2 changed files with 120 additions and 0 deletions
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5
kernel.spec
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@ -787,6 +787,7 @@ Patch12523: keys-fix-rcu-no-lock-warning-in-keyctl-session-to-parent.patch
Patch12530: pci-msi-remove-unsafe-and-unnecessary-hardware-access.patch
Patch12531: pci-msi-restore-read_msi_msg_desc-add-get_cached_msi_msg_desc.patch
Patch12532: x86-tsc-sched-recompute-cyc2ns_offset-s-during-resume-from-sleep-states.patch
%endif
@ -1487,6 +1488,8 @@ ApplyPatch keys-fix-rcu-no-lock-warning-in-keyctl-session-to-parent.patch
# Fix unsafe access to MSI registers during suspend
ApplyPatch pci-msi-remove-unsafe-and-unnecessary-hardware-access.patch
ApplyPatch pci-msi-restore-read_msi_msg_desc-add-get_cached_msi_msg_desc.patch
# Fix scheduler load balancing after suspend/resume cycle
ApplyPatch x86-tsc-sched-recompute-cyc2ns_offset-s-during-resume-from-sleep-states.patch
# END OF PATCH APPLICATIONS
@ -2114,6 +2117,8 @@ fi
- Fix unsafe access to MSI registers during suspend
(pci-msi-remove-unsafe-and-unnecessary-hardware-access.patch,
pci-msi-restore-read_msi_msg_desc-add-get_cached_msi_msg_desc.patch)
- x86-tsc-sched-recompute-cyc2ns_offset-s-during-resume-from-sleep-states.patch
Fix load balancing after suspend/resume cycle (taken from 2.6.32 stable queue)
* Fri Sep 03 2010 Chuck Ebbert <cebbert@redhat.com> 2.6.34.6-52
- acpi-ec-pm-fix-race-between-ec-transactions-and-system-suspend.patch:

115
x86-tsc-sched-recompute-cyc2ns_offset-s-during-resume-from-sleep-states.patch Normal file
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@ -0,0 +1,115 @@
From cd7240c0b900eb6d690ccee088a6c9b46dae815a Mon Sep 17 00:00:00 2001
From: Suresh Siddha <suresh.b.siddha@intel.com>
Date: Thu, 19 Aug 2010 17:03:38 -0700
Subject: x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states
From: Suresh Siddha <suresh.b.siddha@intel.com>
commit cd7240c0b900eb6d690ccee088a6c9b46dae815a upstream.
TSC's get reset after suspend/resume (even on cpu's with invariant TSC
which runs at a constant rate across ACPI P-, C- and T-states). And in
some systems BIOS seem to reinit TSC to arbitrary large value (still
sync'd across cpu's) during resume.
This leads to a scenario of scheduler rq->clock (sched_clock_cpu()) less
than rq->age_stamp (introduced in 2.6.32). This leads to a big value
returned by scale_rt_power() and the resulting big group power set by the
update_group_power() is causing improper load balancing between busy and
idle cpu's after suspend/resume.
This resulted in multi-threaded workloads (like kernel-compilation) go
slower after suspend/resume cycle on core i5 laptops.
Fix this by recomputing cyc2ns_offset's during resume, so that
sched_clock() continues from the point where it was left off during
suspend.
Reported-by: Florian Pritz <flo@xssn.at>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1282262618.2675.24.camel@sbsiddha-MOBL3.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/x86/include/asm/tsc.h | 2 ++
arch/x86/kernel/tsc.c | 38 ++++++++++++++++++++++++++++++++++++++
arch/x86/power/cpu.c | 2 ++
3 files changed, 42 insertions(+)
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -59,5 +59,7 @@ extern void check_tsc_sync_source(int cp
extern void check_tsc_sync_target(void);
extern int notsc_setup(char *);
+extern void save_sched_clock_state(void);
+extern void restore_sched_clock_state(void);
#endif /* _ASM_X86_TSC_H */
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -626,6 +626,44 @@ static void set_cyc2ns_scale(unsigned lo
local_irq_restore(flags);
}
+static unsigned long long cyc2ns_suspend;
+
+void save_sched_clock_state(void)
+{
+ if (!sched_clock_stable)
+ return;
+
+ cyc2ns_suspend = sched_clock();
+}
+
+/*
+ * Even on processors with invariant TSC, TSC gets reset in some the
+ * ACPI system sleep states. And in some systems BIOS seem to reinit TSC to
+ * arbitrary value (still sync'd across cpu's) during resume from such sleep
+ * states. To cope up with this, recompute the cyc2ns_offset for each cpu so
+ * that sched_clock() continues from the point where it was left off during
+ * suspend.
+ */
+void restore_sched_clock_state(void)
+{
+ unsigned long long offset;
+ unsigned long flags;
+ int cpu;
+
+ if (!sched_clock_stable)
+ return;
+
+ local_irq_save(flags);
+
+ get_cpu_var(cyc2ns_offset) = 0;
+ offset = cyc2ns_suspend - sched_clock();
+
+ for_each_possible_cpu(cpu)
+ per_cpu(cyc2ns_offset, cpu) = offset;
+
+ local_irq_restore(flags);
+}
+
#ifdef CONFIG_CPU_FREQ
/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -112,6 +112,7 @@ static void __save_processor_state(struc
void save_processor_state(void)
{
__save_processor_state(&saved_context);
+ save_sched_clock_state();
}
#ifdef CONFIG_X86_32
EXPORT_SYMBOL(save_processor_state);
@@ -253,6 +254,7 @@ static void __restore_processor_state(st
void restore_processor_state(void)
{
__restore_processor_state(&saved_context);
+ restore_sched_clock_state();
}
#ifdef CONFIG_X86_32
EXPORT_SYMBOL(restore_processor_state);