From mboxrd@z Thu Jan 1 00:00:00 1970
From: bugzilla-daemon@bugzilla.kernel.org
Subject: [Bug 18302] New: [BUG] bad performance and system stalls when using
dm-crypt
Date: Sun, 12 Sep 2010 11:00:32 GMT
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https://bugzilla.kernel.org/show_bug.cgi?id=18302
Summary: [BUG] bad performance and system stalls when using
dm-crypt
Product: File System
Version: 2.5
Kernel Version: 2.6.35.4
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: ext3
AssignedTo: fs_ext3@kernel-bugs.osdl.org
ReportedBy: db.pub.mail@gmail.com
Regression: No
Please see
http://thread.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/4558 for the
full mailing list thread that is related to my bug report here :)
Summary:
'Right, I see the issue as the following: requesting a lot of writes
and then a number of read operations from different processes leads to
a *poor* outcome.
I say this because if I do "dd /dev/zero of=/tmp/DELETEME"
after a short time the entire system stalls and it really is *very*
difficult to end the dd, which is writing to the disk :)'
---> The first post in the thread I sent to the dm-crypt list :)
I am not sure if this really is a bug or just expected behaviour with
ext3 in ordered mode with luks / dm-crypt adding some extra latency
...
----
I am experiencing really bad performance and a fair amount of system
stalls using dm-crypt(luks) on debian lenny with with an ext3
ordered mode /
"
Version: 1
Cipher name: aes
Cipher mode: cbc-essiv:sha256
Hash spec: sha1
"
/dev/mapper/foo-root on / type ext3 (rw,relatime,errors=remount-ro)
Swap is also within the luks partition.
The kernel version is 2.6.35.4.
A simple test is just to dd if=/dev/zero of=DELETEME for a short time
and the system will stall rather a lot - it is not a complete lock up
- just the entire system is unresponsive for large periods at a time
(from around 30seconds - to 2 minutes). This may be related to
http://thread.gmane.org/gmane.linux.kernel.mm/51444 .
The system is a 6 core amd phenom with 4gb of ram - the hard drive is
a WD 1TB sata 3 drive hooked up to a (sata 3 controller)
00:11.0 SATA controller: ATI Technologies Inc SB700/SB800 SATA
Controller [IDE mode] (rev 40)
00:11.0 SATA controller: ATI Technologies Inc SB700/SB800 SATA
Controller [IDE mode] (rev 40) (prog-if 01 [AHCI 1.0])
Subsystem: ASUSTeK Computer Inc. Device 8443
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR+ FastB2B- DisINTx+
Status: Cap+ 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium
>TAbort- SERR-
Capabilities: [a4] PCIe advanced features
Kernel driver in use: ahci
Kernel modules: ahci
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