Wind River Support Network

HomeDefectsOVP-275

Fixed

OVP-275 : cyclictest results dropped since lx18---lx19 (since Add support for lazy preemption)

Created: Jul 25, 2013 Updated: Mar 11, 2016

Resolved Date: Nov 23, 2013

Found In Version: 5.0.1

Fix Version: 5.0.1.10

Severity: Standard

Applicable for: Wind River Linux 5

Component/s: Kernel

Description

lv19a

root@localhost:~# cyclictest -S -m -p 80 -l 100000

T: 1 (  771) P:80 I:1500 C:  66671 Min:      6 Act:    7 Avg:    8 Max:      25


lv18


T: 1 (  733) P:80 I:1500 C:   6673 Min:      4 Act:    4 Avg:    4 Max:      12

Workaround

revert 
commit 38badba63e7d17332679301eff22335b4823c9e6
Author: Paul Gortmaker <paul.gortmaker@windriver.com>
Date:   Fri Jul 12 15:09:55 2013 -0400

     kvm/lapic: temporarily mask irqsafe flag

     A partial revert of:

       commit 5345ad1661edb624aeca87f5fb08abccd4414f68
       Author: Thomas Gleixner <tglx@linutronix.de>
       Date:   Sun Dec 18 13:31:32 2011 +0100

           kvm: Make lapic hrtimer irq safe

           Avoid going through the softirq.

     It seems that forcing events to be handled in irq context
     is causing guest hangs that look like dropped timer events.
     Bisect led to this change.  Needs more investigation.

     Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Steps to Reproduce

boot with tuned guest,and run cyclictetst by revert "38badba63e7d17332679301eff22335b4823c9e6" or not revert