linux-kernel - [PATCH 0/4] MIPS: Guest timekeeping improvements

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Date:	Fri, 22 Apr 2016 18:19:13 +0100
From:	James Hogan <james.hogan@...tec.com>
To:	Ralf Baechle <ralf@...ux-mips.org>
CC:	James Hogan <james.hogan@...tec.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	<linux-mips@...ux-mips.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/4] MIPS: Guest timekeeping improvements

These patches improve timekeeping of MIPS/Malta kernels running in a KVM
guest.

Patch 2 fixes malta frequency calculation under virtualisation,
especially on very slow targets (FPGA / emulators). Patch 1 is a minor
fix for something I noticed while writing patch 2.

Patch 3 drops the use of the PIT timer for Malta, which is slow to
emulate with KVM + QEMU.

Finally patch 4 calculates min_delta_ns of cevt-r4k dynamically to
handle virtualised environments with software emulated Count/Compare,
and where Count frequency may not be directly related to actual CPU
speed (and so the static value of 0x300 may be no good).

James Hogan (4):
  MIPS: malta-time: Start GIC count before syncing to RTC
  MIPS: malta-time: Take seconds into account
  MIPS: malta-time: Don't use PIT timer for cevt/csrc
  MIPS: cevt-r4k: Dynamically calculate min_delta_ns

 arch/mips/Kconfig                |  1 -
 arch/mips/kernel/cevt-r4k.c      | 82 +++++++++++++++++++++++++++++++++++++++-
 arch/mips/mti-malta/malta-time.c | 50 +++++++++++++++---------
 3 files changed, 113 insertions(+), 20 deletions(-)

Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-mips@...ux-mips.org
Cc: linux-kernel@...r.kernel.org
-- 
2.4.10