Public bug reported:
Binary package hint: util-linux
Swapoff takes very long to disable the swap.
The swap is being removed at speed of 0.5 MB/s, while the hard drive speed is
60 MB/s;
No other programs are using harddrive a lot, system is not under high load etc.
Ubuntu 9.10 on quad core.
Swap partition is encrypted.
Top (atop) shows near 100% hard drive usage
DSK | sdc | busy 88% | read 56 | write 0 | avio 9 ms
|
but the device transfer is low (kdesysguard)
0.4 MiB/s on /dev/sdc reads, and 0 on writes
/etc/crypttab
swap1 /dev/sdc2 /dev/random
swap,noearly,noauto,check=un_vol_id,loud
r...@lcwood(2009-11-22_14:52:41)~$ swapon -s
Filename Type Size Used Priority
/dev/mapper/swap1 partition 4000176 231704 -1
r...@lcwood(2009-11-22_14:52:54)~$ swapon -s
Filename Type Size Used Priority
/dev/mapper/swap1 partition 4000176 226628 -1
$ vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
6 1 246340 1313240 261952 606296 1 1 63 111 9 13 3 2 95 1
hdparm -Tt /dev/sdc
/dev/sdc:
Timing cached reads: 2918 MB in 2.00 seconds = 1459.14 MB/sec
Timing buffered disk reads: 210 MB in 3.06 seconds = 68.61 MB/sec
System load is low (atop)
PRC | sys 0.10s | user 0.11s | #proc 368 | #zombie 0 | #exit 0 |
CPU | sys 12% | user 16% | irq 0% | idle 287% | wait 89% |
The CPU load was around 25% - so one entire core was used...
Perhaps this is because swapoff took so long to decrypt the data?
But 0.5 MB/s for encrption on quad core intel ~2.6 GHz CPU is too slow,
it should be more like 20-50 MB/s, even when using just 1 core/thread.
ProblemType: Bug
Architecture: amd64
Date: Sun Nov 22 14:51:33 2009
DistroRelease: Ubuntu 9.10
NonfreeKernelModules: nvidia
Package: mount 2.16-1ubuntu5
ProcEnviron:
LANGUAGE=
PATH=(custom, user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-14.48-generic
SourcePackage: util-linux
Uname: Linux 2.6.31-14-generic x86_64
** Affects: util-linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug
--
9.10 amd 64 - Very slow swapoff performance (0.5 MB/s) on encrypted device (but
fast CPU)
https://bugs.launchpad.net/bugs/486666
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