x86/mwait-idle: update ICX C6 data

Change IceLake Xeon C6 latency from 128 us to 170 us. The latency
was measured with the "wult" tool and corresponds to the 99.99th
percentile when measuring with the "nic" method. Note, the 128 us
figure correspond to the median latency, but in intel_idle we use
the "worst case" latency figure instead.

C6 target residency was increased from 384 us to 600 us, which may
result in less C6 residency in some workloads. This value was tested
and compared to values 384, and 1000. Value 600 is a reasonable
tradeoff between power and performance.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
[Linux commit: d484b8bfc6fa71a088e4ac85d9ce11aa0385867e]
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>

diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index 5c9dc0405f92757ebdb787042851e86c6746b0bd..15c4996581aeff1d3b2a63f99f69e1d00862d6ff 100644 (file)
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -574,8 +574,8 @@ static const struct cpuidle_state icx_cstates[] = {
        {
                .name = "C6-ICX",
                .flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
-               .exit_latency = 128,
-               .target_residency = 384,
+               .exit_latency = 170,
+               .target_residency = 600,
        },
        {}
 };