qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
* [Qemu-devel] [Bug 1751264] [NEW] qemu-img convert issue in a tmpfs partition
@ 2018-02-23 12:50 Teddy VALETTE
  2018-02-26 13:28 ` [Qemu-devel] [Bug 1751264] " Teddy VALETTE
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Teddy VALETTE @ 2018-02-23 12:50 UTC (permalink / raw)
  To: qemu-devel

Public bug reported:

qemu-img convert command is slow when the file to convert is located in
a tmpfs formatted partition.

v2.1.0 on debian/jessie x64, ext4: 10m14s
v2.1.0 on debian/jessie x64, tmpfs: 10m15s

v2.1.0 on debian/stretch x64, ext4: 11m9s
v2.1.0 on debian/stretch x64, tmpfs: 10m21.362s

v2.8.0 on debian/jessie x64, ext4: 10m21s
v2.8.0 on debian/jessie x64, tmpfs: Too long

v2.8.0 on debian/stretch x64, ext4: 10m42s
v2.8.0 on debian/stretch x64, tmpfs: Too long

It seems that the issue is caused by this commit :
https://github.com/qemu/qemu/commit/690c7301600162421b928c7f26fd488fd8fa464e

In order to reproduce this bug :

1/ mount a tmpfs partition : mount -t tmpfs tmpfs /tmp
2/ get a vmdk file (we used a 15GB image) and put it on /tmp
3/ run the 'qemu-img convert -O qcow2 /tmp/file.vmdk /path/to/destination' command

When we trace the process, we can see that there's a lseek loop which is
very slow (compare to outside a tmpfs partition).

** Affects: qemu
     Importance: Undecided
         Status: New


** Tags: qemu-img

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1751264

Title:
  qemu-img convert issue in a tmpfs partition

Status in QEMU:
  New

Bug description:
  qemu-img convert command is slow when the file to convert is located
  in a tmpfs formatted partition.

  v2.1.0 on debian/jessie x64, ext4: 10m14s
  v2.1.0 on debian/jessie x64, tmpfs: 10m15s

  v2.1.0 on debian/stretch x64, ext4: 11m9s
  v2.1.0 on debian/stretch x64, tmpfs: 10m21.362s

  v2.8.0 on debian/jessie x64, ext4: 10m21s
  v2.8.0 on debian/jessie x64, tmpfs: Too long

  v2.8.0 on debian/stretch x64, ext4: 10m42s
  v2.8.0 on debian/stretch x64, tmpfs: Too long

  It seems that the issue is caused by this commit :
  https://github.com/qemu/qemu/commit/690c7301600162421b928c7f26fd488fd8fa464e

  In order to reproduce this bug :

  1/ mount a tmpfs partition : mount -t tmpfs tmpfs /tmp
  2/ get a vmdk file (we used a 15GB image) and put it on /tmp
  3/ run the 'qemu-img convert -O qcow2 /tmp/file.vmdk /path/to/destination' command

  When we trace the process, we can see that there's a lseek loop which
  is very slow (compare to outside a tmpfs partition).

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1751264/+subscriptions

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-06-21  4:34 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-02-23 12:50 [Qemu-devel] [Bug 1751264] [NEW] qemu-img convert issue in a tmpfs partition Teddy VALETTE
2018-02-26 13:28 ` [Qemu-devel] [Bug 1751264] " Teddy VALETTE
2018-02-26 16:08 ` Max Reitz
2021-04-21  6:28 ` Thomas Huth
2021-06-21  4:17 ` Launchpad Bug Tracker

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).