[xen staging] x86/mwait-idle: update ICX C6 data

[patchbot@xxxxxxx]

commit b07050e1e8f749720485c6c7e75ea46add32c20a
Author:     Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
AuthorDate: Wed Jan 19 13:45:11 2022 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jan 19 13:45:11 2022 +0100

    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@xxxxxxxxxxxxxxx>
    Acked-by: Zhang Rui <rui.zhang@xxxxxxxxx>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
    [Linux commit: d484b8bfc6fa71a088e4ac85d9ce11aa0385867e]
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/cpu/mwait-idle.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index 5c9dc0405f..15c4996581 100644
--- 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,
        },
        {}
 };
--
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