e4defrag has fatal CPU performance bottleneck
Bug #1398434 reported by
Karl-Philipp Richter
This bug affects 1 person
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| e2fsprogs (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
Bug Description
During defragmentation of a 5 TB ext4 filesystem with one 600 GB file with current value of 300000 and optimal value of 300 shown by `e4defrag -c`, `e4defrag' seems to suffer from a huge CPU performance bottleneck. Over hours only one CPU core is used (-> no parallelization) and there's almost no I/O during that time <1 % of the underlying device's capabilities.
ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: e2fsprogs 1.42.10-1.1ubuntu1
Uname: Linux 3.17.4-
ApportVersion: 2.14.7-0ubuntu8
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Dec 2 16:29:12 2014
SourcePackage: e2fsprogs
UpgradeStatus: No upgrade log present (probably fresh install)
Revision history for this message
| Karl-Philipp Richter (krichter722) wrote | #1 |
Revision history for this message
| Theodore Ts'o (tytso) wrote | #2 |
To post a comment you must log in.
Please strace the e4defrag process to see if it is spinning in userspace or in the kernel. If it is spinning in the kernel, then it's a kernel bug, not an e2fsrpogs problem. And since you're using a non-Ubuntu kernel, you'll need to take this to the upstream linux-ext4 mailing list.
If it turns out to be a case of spinning in the kernel, what we'll want to know is whether you can easily reproduce the problem, and if so, whether you can give us a kernel stack trace by using magic-sysrq-l and magic-sysrq-t.