On some Silvermont-Core/Baytrail-SOC systems,
C1E latency is higher than original specifications.
Although C1E is still enumerated in CPUID.MWAIT.EDX,
we delete the state from intel_idle to avoid latency impact.
Under some conditions, the latency of the C6N-BYT and C6S-BYT states
may exceed the specified values of 40 and 140 usec, respectively.
Increase those values to 300 and 500 usec; to assure
that the hardware does not violate constraints that may be set
by the Linux PM_QOS sub-system.
Also increase the C7-BYT target residency to 4.0 ms from 1.5 ms.
Signed-off-by: Len Brown <len.br...@intel.com>
[Linux commit d7ef76717322c8e2df7d4360b33faa9466cb1a0d]
Signed-off-by: Jan Beulich <jbeul...@suse.com>
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -196,28 +196,22 @@ static const struct cpuidle_state byt_cs
.target_residency = 1,
},
{
- .name = "C1E-BYT",
- .flags = MWAIT2flg(0x01),
- .exit_latency = 15,
- .target_residency = 30,
- },
- {
.name = "C6N-BYT",
.flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
- .exit_latency = 40,
+ .exit_latency = 300,
.target_residency = 275,
},
{
.name = "C6S-BYT",
.flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
- .exit_latency = 140,
+ .exit_latency = 500,
.target_residency = 560,
},
{
.name = "C7-BYT",
.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
.exit_latency = 1200,
- .target_residency = 1500,
+ .target_residency = 4000,
},
{
.name = "C7S-BYT",
mwait-idle: update support for Silvermont Core in Baytrail SOC
On some Silvermont-Core/Baytrail-SOC systems,
C1E latency is higher than original specifications.
Although C1E is still enumerated in CPUID.MWAIT.EDX,
we delete the state from intel_idle to avoid latency impact.
Under some conditions, the latency of the C6N-BYT and C6S-BYT states
may exceed the specified values of 40 and 140 usec, respectively.
Increase those values to 300 and 500 usec; to assure
that the hardware does not violate constraints that may be set
by the Linux PM_QOS sub-system.
Also increase the C7-BYT target residency to 4.0 ms from 1.5 ms.
Signed-off-by: Len Brown <len.br...@intel.com>
[Linux commit d7ef76717322c8e2df7d4360b33faa9466cb1a0d]
Signed-off-by: Jan Beulich <jbeul...@suse.com>
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -196,28 +196,22 @@ static const struct cpuidle_state byt_cs
.target_residency = 1,
},
{
- .name = "C1E-BYT",
- .flags = MWAIT2flg(0x01),
- .exit_latency = 15,
- .target_residency = 30,
- },
- {
.name = "C6N-BYT",
.flags = MWAIT2flg(0x58) | CPUIDLE_FLAG_TLB_FLUSHED,
- .exit_latency = 40,
+ .exit_latency = 300,
.target_residency = 275,
},
{
.name = "C6S-BYT",
.flags = MWAIT2flg(0x52) | CPUIDLE_FLAG_TLB_FLUSHED,
- .exit_latency = 140,
+ .exit_latency = 500,
.target_residency = 560,
},
{
.name = "C7-BYT",
.flags = MWAIT2flg(0x60) | CPUIDLE_FLAG_TLB_FLUSHED,
.exit_latency = 1200,
- .target_residency = 1500,
+ .target_residency = 4000,
},
{
.name = "C7S-BYT",
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