From: lihaiwei.kernel@gmail.com
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: pbonzini@redhat.com, seanjc@google.com, vkuznets@redhat.com,
wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org,
Haiwei Li <lihaiwei@tencent.com>
Subject: [PATCH] kvm: lapic: add module parameters for LAPIC_TIMER_ADVANCE_ADJUST_MAX/MIN
Date: Wed, 3 Mar 2021 10:09:46 +0800 [thread overview]
Message-ID: <20210303020946.26083-1-lihaiwei.kernel@gmail.com> (raw)
From: Haiwei Li <lihaiwei@tencent.com>
In my test environment, advance_expire_delta is frequently greater than
the fixed LAPIC_TIMER_ADVANCE_ADJUST_MAX. And this will hinder the
adjustment.
Adding module parameters for LAPIC_TIMER_ADVANCE_ADJUST_MAX/MIN, so they
can be dynamically adjusted.
Signed-off-by: Haiwei Li <lihaiwei@tencent.com>
---
arch/x86/kvm/lapic.c | 6 ++----
arch/x86/kvm/x86.c | 8 ++++++++
arch/x86/kvm/x86.h | 3 +++
3 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 45d40bf..730c657 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -61,8 +61,6 @@
#define APIC_VECTORS_PER_REG 32
static bool lapic_timer_advance_dynamic __read_mostly;
-#define LAPIC_TIMER_ADVANCE_ADJUST_MIN 100 /* clock cycles */
-#define LAPIC_TIMER_ADVANCE_ADJUST_MAX 10000 /* clock cycles */
#define LAPIC_TIMER_ADVANCE_NS_INIT 1000
#define LAPIC_TIMER_ADVANCE_NS_MAX 5000
/* step-by-step approximation to mitigate fluctuation */
@@ -1563,8 +1561,8 @@ static inline void adjust_lapic_timer_advance(struct kvm_vcpu *vcpu,
u64 ns;
/* Do not adjust for tiny fluctuations or large random spikes. */
- if (abs(advance_expire_delta) > LAPIC_TIMER_ADVANCE_ADJUST_MAX ||
- abs(advance_expire_delta) < LAPIC_TIMER_ADVANCE_ADJUST_MIN)
+ if (abs(advance_expire_delta) > lapic_timer_advance_adjust_cycles_max ||
+ abs(advance_expire_delta) < lapic_timer_advance_adjust_cycles_min)
return;
/* too early */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 828de7d..3bd8d19 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -176,6 +176,14 @@
int __read_mostly pi_inject_timer = -1;
module_param(pi_inject_timer, bint, S_IRUGO | S_IWUSR);
+u64 __read_mostly lapic_timer_advance_adjust_cycles_max = 10000;
+module_param(lapic_timer_advance_adjust_cycles_max, ullong, S_IRUGO | S_IWUSR);
+EXPORT_SYMBOL_GPL(lapic_timer_advance_adjust_cycles_max);
+
+u64 __read_mostly lapic_timer_advance_adjust_cycles_min = 100;
+module_param(lapic_timer_advance_adjust_cycles_min, ullong, S_IRUGO | S_IWUSR);
+EXPORT_SYMBOL_GPL(lapic_timer_advance_adjust_cycles_min);
+
/*
* Restoring the host value for MSRs that are only consumed when running in
* usermode, e.g. SYSCALL MSRs and TSC_AUX, can be deferred until the CPU
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index ee6e010..3f7eca0 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -305,6 +305,9 @@ static inline bool kvm_mpx_supported(void)
extern int pi_inject_timer;
+extern u64 lapic_timer_advance_adjust_cycles_max;
+extern u64 lapic_timer_advance_adjust_cycles_min;
+
extern struct static_key kvm_no_apic_vcpu;
extern bool report_ignored_msrs;
--
1.8.3.1
next reply other threads:[~2021-03-03 7:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 2:09 lihaiwei.kernel [this message]
2021-03-03 2:39 ` [PATCH] kvm: lapic: add module parameters for LAPIC_TIMER_ADVANCE_ADJUST_MAX/MIN Haiwei Li
2021-03-09 23:42 ` Sean Christopherson
2021-03-10 9:15 ` Haiwei Li
2021-03-13 0:58 ` Sean Christopherson
2021-03-13 1:31 ` Haiwei Li
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