linux-kernel - Re: [PATCH] Do not modify MSR_IA32_ENERGY_PERF

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJvTdKnJSqCxVhriMUJfeRL=ogpG2GYgSJ5anvbjrbm_rNyKcQ@mail.gmail.com>
Date:	Mon, 7 Mar 2016 19:50:57 -0500
From:	Len Brown <lenb@...nel.org>
To:	"Rafael J. Wysocki" <rafael@...nel.org>
Cc:	Thomas Renninger <trenn@...e.de>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Ingo Molnar <mingo@...nel.org>, X86 ML <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: Re: [PATCH] Do not modify MSR_IA32_ENERGY_PERF_BIAS in kernel

> But with Broadwell-EP processor (E5-2687W v4) the CPU will not enter turbo modes
> if this value is not set to performance

BDX-EP supports HWP.
Are these failing machines running in HWP mode?

(On BDX-EP, and only on BDX-EP, EPB acts to set the BIAS for HWP,
 because that processor doesn't yet have EPP.)

-- 
Len Brown, Intel Open Source Technology Center