Re: High CPU utilization on Windows Guest OS with random write workload when using Cinder Volume (libgfapi)

[qingwei wei <tchengwee@xxxxxxxxx>]

Hi,

I realized this happens only when i use libgfapi and there is no such problem when i use fuse. As libgfapi is started by qemu-kvm, could this be the reason why CPU utilization is high on Windows guest?

Cw

On Tue, Mar 8, 2016 at 4:38 PM, qingwei wei <tchengwee@xxxxxxxxx> wrote:

Hi all,

I am currently testing running Openstack instance on Cinder volume with libgfapi. This instance is the Windows instance and i found that when running random 4k write workload, the CPU utilization is very high,  90% CPU utilization with about 86% in privileged time. I also tested the workload with volume from NFS and the CPU utilization is only around 5%. Is there any reason why is that so? Appreciate on any comments and suggestions.

Details.

Workload generator: IOMeter

Instance: Windows 2008R2

Openstack Host: CentOS 7

Workload: 4kb random write, 4 workers with each worker configure to have 4 outstanding IOs

Gluster server and client version: 3.7.8

Gluster info

Volume Name: g37test

Type: Distribute

Volume ID: 27947421-111b-4727-bcaf-bafe73debe07

Status: Started

Number of Bricks: 1

Transport-type: tcp

Bricks:

Brick1: 192.168.99.4:/mnt/ssd/g37test

Options Reconfigured:

performance.readdir-ahead: on

nfs.disable: true

performance.io-cache: off

performance.quick-read: off

server.allow-insecure: on

storage.owner-uid: 165

storage.owner-gid: 165

IOmeter result:

Glusterfs

======

IOPS: ~5800

CPU utilization: ~90% 

NFS

===

IOPS: ~6000

CPU Utilization: ~5-6%

Cw

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