** Also affects: qemu
Importance: Undecided
Status: New
** Also affects: ubuntu-power-systems
Importance: Undecided
Status: New
** No longer affects: qemu
** Changed in: ubuntu-power-systems
Assignee: (unassigned) => Canonical Server Team (canonical-server)
** Changed in: ubuntu-power-systems
Importance: Undecided => Medium
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https://bugs.launchpad.net/bugs/1853042
Title:
Ubuntu 18.04 - vm disk i/o performance issue when using file system
passthrough
Status in The Ubuntu-power-systems project:
New
Status in qemu package in Ubuntu:
New
Bug description:
== Comment: #0 - I-HSIN CHUNG <ihch...@us.ibm.com> - 2019-11-15 12:35:05 ==
---Problem Description---
Ubuntu 18.04 - vm disk i/o performance issue when using file system
passthrough
Contact Information = ihch...@us.ibm.com
---uname output---
Linux css-host-22 4.15.0-1039-ibm-gt #41-Ubuntu SMP Wed Oct 2 10:52:25 UTC
2019 ppc64le ppc64le ppc64le GNU/Linux (host) Linux ubuntu 4.15.0-65-generic
#74-Ubuntu SMP Tue Sep 17 17:08:54 UTC 2019 ppc64le ppc64le ppc64le GNU/Linux
(vm)
Machine Type = p9/ac922
---Debugger---
A debugger is not configured
---Steps to Reproduce---
1. Env: Ubuntu 18.04.3 LTS?Genesis kernel linux-ibm-gt - 4.15.0-1039.41?qemu
1:2.11+dfsg-1ubuntu7.18 ibmcloud0.3 or 1:2.11+dfsg-1ubuntu7.19
ibm-cloud1?fio-3.15-4-g029b
2. execute run.sh to run fio benchmark:
2.1) run.sh:
#!/bin/bash
for bs in 4k 16m
do
for rwmixread in 0 25 50 75 100
do
for numjobs in 1 4 16 64
do
echo ./fio j1.txt --bs=$bs --rwmixread=$rwmixread --numjobs=$numjobs
./fio j1.txt --bs=$bs --rwmixread=$rwmixread --numjobs=$numjobs
done
done
done
2.2) j1.txt:
[global]
direct=1
rw=randrw
refill_buffers
norandommap
randrepeat=0
ioengine=libaio
iodepth=64
runtime=60
allow_mounted_write=1
[job2]
new_group
filename=/dev/vdb
filesize=1000g
cpus_allowed=0-63
numa_cpu_nodes=0
numa_mem_policy=bind:0
3. performance profile:
device passthrough performance for the nvme:
http://css-host-22.watson.ibm.com/rundir/nvme_vm_perf_vm/20191011-112156/html/#/measurement/vm/ubuntu
(I/O bandwidth achieved inside VM in GB/s range)
file system passthrough
http://css-host-22.watson.ibm.com/rundir/nvme_vm_perf_vm/20191106-123613/html/#/measurement/vm/ubuntu
(I/o bandwidth achieved inside the VM is very low)
desired performance when using file system passthrough should be similar to
the device passthrough
Userspace tool common name: fio
The userspace tool has the following bit modes: should be 64 bit
Userspace rpm: ?
Userspace tool obtained from project website: na
*Additional Instructions for ihch...@us.ibm.com:
-Post a private note with access information to the machine that the bug is
occuring on.
-Attach ltrace and strace of userspace application.
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