On ICX platform, the CPU frequency will slowly ramp up
when woken up from C-states deeper than/equals to C1E,
and since C1E auto-promotion is enabled by default,
this might cause unexpected result.
Thus this patch disables C1E auto-promotion and expose
C1E as a separate idle state, so that the C1E and C6 can
be disabled via sysfs when necessary.
Besides C1 and C1E, the exit latency of C6 was measured
by a dedicated tool. However the exit latency(41us) exposed
by _CST is much smaller than the one measured(128us). This
is probably due to the _CST uses the exit latency when woken
up from PC0+C6, rather than PC6+C6 when C6 was measured.
Tested-by: Artem Bityutskiy <artem.bityuts...@linux.intel.com>
Acked-by: Artem Bityutskiy <artem.bityuts...@linux.intel.com>
Signed-off-by: Zhang Rui <rui.zh...@intel.com>
Signed-off-by: Chen Yu <yu.c.c...@intel.com>
---
drivers/idle/intel_idle.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index f4495841bf68..1eab606d858b 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -752,6 +752,35 @@ static struct cpuidle_state skx_cstates[] __initdata = {
.enter = NULL }
};
+static struct cpuidle_state icx_cstates[] __initdata = {
+ {
+ .name = "C1",
+ .desc = "MWAIT 0x00",
+ .flags = MWAIT2flg(0x00),
+ .exit_latency = 1,
+ .target_residency = 1,
+ .enter = &intel_idle,
+ .enter_s2idle = intel_idle_s2idle, },
+ {
+ .name = "C1E",
+ .desc = "MWAIT 0x01",
+ .flags = MWAIT2flg(0x01) | CPUIDLE_FLAG_ALWAYS_ENABLE,
+ .exit_latency = 4,
+ .target_residency = 4,
+ .enter = &intel_idle,
+ .enter_s2idle = intel_idle_s2idle, },
+ {
+ .name = "C6",
+ .desc = "MWAIT 0x20",
+ .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
+ .exit_latency = 128,
+ .target_residency = 384,
+ .enter = &intel_idle,
+ .enter_s2idle = intel_idle_s2idle, },
+ {
+ .enter = NULL }
+};
+
static struct cpuidle_state atom_cstates[] __initdata = {
{
.name = "C1E",
@@ -1056,6 +1085,12 @@ static const struct idle_cpu idle_cpu_skx __initconst = {
.use_acpi = true,
};
+static const struct idle_cpu idle_cpu_icx __initconst = {
+ .state_table = icx_cstates,
+ .disable_promotion_to_c1e = true,
+ .use_acpi = true,
+};
+
static const struct idle_cpu idle_cpu_avn __initconst = {
.state_table = avn_cstates,
.disable_promotion_to_c1e = true,
@@ -1110,6 +1145,7 @@ static const struct x86_cpu_id intel_idle_ids[]
__initconst = {
X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L, &idle_cpu_skl),
X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE, &idle_cpu_skl),
X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_X, &idle_cpu_skx),
+ X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, &idle_cpu_icx),
X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNL, &idle_cpu_knl),
X86_MATCH_INTEL_FAM6_MODEL(XEON_PHI_KNM, &idle_cpu_knl),
X86_MATCH_INTEL_FAM6_MODEL(ATOM_GOLDMONT, &idle_cpu_bxt),
--
2.17.1
