AppVM Speed is Slow

User Support General
1

Hi

When I run on bare metal

$ sudo hdparm -t /dev/nvme1n1

The speed test is about 10x of what it is when inside QubesOS AppVM:

/dev/nvme1n1:
 Timing buffered disk reads: 7058 MB in  3.00 seconds = 2320.18 MB/sec

however, if on the same hardware I boot QubesOS open an AppVM and run the same test

$ sudo hdparm -t /dev/xvdb

The output is very different (slow)

/dev/xvdb:
 Timing buffered disk reads: 638 MB in  3.01 seconds = 212.18 MB/sec
  • Is it normal?
  • Is it possible to make AppVM as fast as when it runs Linux on bare metal?
  • Cold you share your tests results?

Thanks for your help!

2

@solene - thank you very much for the NV41 review blog I read just now. Would you be able to run this test inside of an appvm and share read speed?

3

Try to assign the number of VCPUs to be the same as the number of your physical CPU threads for your qube.

4

CPU: 13900K, Drive: Samsung 990 Pro

Dom0 from nvme0n1: ~2200MB/s

From /dev/xvdb
appvm on ecore: ~1400MB/s
appvm on pcore: ~2300MB/s

5

Thanks for your comments! I just did, got a bit better result:

AppVM

$ sudo hdparm -t /dev/xvdb

/dev/xvdb:
 Timing buffered disk reads: 1852 MB in  3.00 seconds = 616.88 MB/sec

Dom0

$ sudo hdparm -t /dev/nvme0n1

/dev/nvme0n1:
 Timing buffered disk reads: 8164 MB in  3.00 seconds = 2721.31 MB/sec

I have similar tests results on two different laptops - perhaps it is something to do with the installation process / configuration vm-pool data volumes?

6

That is nice! I wish I ad the same performance. Did you configure vm-pool in a custom way during QubesOS install process?

7

I’m using btrfs, but I didn’t change the settings, it’s the installer defaults.

8

In an AppVM, three times in a row:

user@T ~> sudo hdparm -t /dev/xvdb

/dev/xvdb:
 Timing buffered disk reads: 1636 MB in  3.00 seconds = 544.77 MB/sec
user@T ~> sudo hdparm -t /dev/xvdb

/dev/xvdb:
 Timing buffered disk reads: 1580 MB in  3.00 seconds = 526.63 MB/sec
user@T ~> sudo hdparm -t /dev/xvdb

/dev/xvdb:
 Timing buffered disk reads: 1632 MB in  3.00 seconds = 543.97 MB/sec

and dom0

[root@dom0 ~]# hdparm -t /dev/nvme0n1

/dev/nvme0n1:
 Timing buffered disk reads: 6026 MB in  3.00 seconds = 2008.37 MB/sec
[root@dom0 ~]# hdparm -t /dev/nvme0n1

/dev/nvme0n1:
 Timing buffered disk reads: 6128 MB in  3.00 seconds = 2042.41 MB/sec
[root@dom0 ~]# hdparm -t /dev/nvme0n1

/dev/nvme0n1:
 Timing buffered disk reads: 6306 MB in  3.00 seconds = 2101.41 MB/sec