Comment # 18 on bug 1131437 from Jan Kara

BTW, impera has just bisected dbench4 regression between 5.0 and 5.1 on hardy2
to:

Last good commit: a8e1942d97dcc44d1425807c71a4252f9e3b53b6
First bad commit: b8bd1581aa6110eb234c0d424eccd3f32d7317e6
>From b8bd1581aa6110eb234c0d424eccd3f32d7317e6 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Thu, 7 Feb 2019 12:51:04 +0100
Subject: [PATCH] cpufreq: intel_pstate: Rework iowait boosting to be less
 aggressive
The current iowait boosting mechanism in intel_pstate_update_util()
is quite aggressive, as it goes to the maximum P-state right away,
and may cause excessive amounts of energy to be used, which is not
desirable and arguably isn't necessary too.
Follow commit a5a0809bc58e ("cpufreq: schedutil: Make iowait boost
more energy efficient") that reworked the analogous iowait boost
mechanism in the schedutil governor and make the iowait boosting
in intel_pstate_update_util() work along the same lines.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>