From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Date: Mon, 30 Jul 2018 15:00:29 -0700
Subject: cpufreq: intel_pstate: Limit the scope of HWP dynamic boost platforms
Patch-mainline: v4.18-rc8
Git-commit: 01e61a42a5d345a4c0205889498f0c9a0fb9ee8c
References: bsc#1066110

Dynamic boosting of HWP performance on IO wake showed significant
improvement to IO workloads. This series was intended for Skylake Xeon
platforms only and feature was enabled by default based on CPU model
number.

But some Xeon platforms reused the Skylake desktop CPU model number. This
caused some undesirable side effects to some graphics workloads. Since
they are heavily IO bound, the increase in CPU performance decreased the
power available for GPU to do its computing and hence decrease in graphics
benchmark performance.

For example on a Skylake desktop, GpuTest benchmark showed average FPS
reduction from 529 to 506.

This change makes sure that HWP boost feature is only enabled for Skylake
server platforms by using ACPI FADT preferred PM Profile. If some desktop
users wants to get benefit of boost, they can still enable boost from
intel_pstate sysfs attribute "hwp_dynamic_boost".

Fixes: 41ab43c9c89e (cpufreq: intel_pstate: enable boost for Skylake Xeon)
Link: https://bugs.freedesktop.org/show_bug.cgi?id=107410
Reported-by: Eero Tamminen <eero.t.tamminen@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Giovanni Gherdovich <ggherdovich@suse.cz>
---
 drivers/cpufreq/intel_pstate.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -375,12 +375,20 @@ static DEFINE_MUTEX(intel_pstate_limits_
 
 #ifdef CONFIG_ACPI
 
-static bool intel_pstate_get_ppc_enable_status(void)
+static bool intel_pstate_acpi_pm_profile_server(void)
 {
 	if (acpi_gbl_FADT.preferred_profile == PM_ENTERPRISE_SERVER ||
 	    acpi_gbl_FADT.preferred_profile == PM_PERFORMANCE_SERVER)
 		return true;
 
+	return false;
+}
+
+static bool intel_pstate_get_ppc_enable_status(void)
+{
+	if (intel_pstate_acpi_pm_profile_server())
+		return true;
+
 	return acpi_ppc;
 }
 
@@ -523,6 +531,11 @@ static inline void intel_pstate_init_acp
 static inline void intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
 {
 }
+
+static inline bool intel_pstate_acpi_pm_profile_server(void)
+{
+	return false;
+}
 #endif
 
 static signed int pid_calc(struct _pid *pid, int32_t busy)
@@ -2113,7 +2126,7 @@ static int intel_pstate_init_cpu(unsigne
 		intel_pstate_hwp_enable(cpu);
 
 		id = x86_match_cpu(intel_pstate_hwp_boost_ids);
-		if (id)
+		if (id && intel_pstate_acpi_pm_profile_server())
 			hwp_boost = true;
 	} else if (pid_in_use()) {
 		intel_pstate_pid_reset(cpu);