Bug 666477
Summary: | test XFS/FUSE heavy writeback workloads (also swapping too) | ||
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Product: | Red Hat Enterprise Linux 5 | Reporter: | Qian Cai <qcai> |
Component: | kernel | Assignee: | Red Hat Kernel Manager <kernel-mgr> |
Status: | CLOSED CURRENTRELEASE | QA Contact: | Boris Ranto <branto> |
Severity: | medium | Docs Contact: | |
Priority: | medium | ||
Version: | 5.6 | CC: | branto, yanwang |
Target Milestone: | rc | Keywords: | TestOnly |
Target Release: | --- | ||
Hardware: | Unspecified | ||
OS: | Linux | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | Bug Fix | |
Doc Text: | Story Points: | --- | |
Clone Of: | Environment: | ||
Last Closed: | 2011-01-18 02:22:34 UTC | Type: | --- |
Regression: | --- | Mount Type: | --- |
Documentation: | --- | CRM: | |
Verified Versions: | Category: | --- | |
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
Cloudforms Team: | --- | Target Upstream Version: | |
Embargoed: |
Description
Qian Cai
2010-12-31 01:48:16 UTC
This could be something like, https://bugzilla.redhat.com/show_bug.cgi?id=617035 Did you have any specific device in mind? What did you mean by 'writeback'? Having hdd with the write back cache turned on? What kind of swapping? Should I limit the system memory so that swap is needed or any other swapping? What kind of tunables? mount options or something in /sys/ or /proc/sys/ directories? What I have in mind is, 1) starting xfs/fuse heavy with multiple aggressive writers (better to use a fast storage arrays), so there are pretty of memory is occupying by file cache. Continue the workloads... 2) at the same time, putting the system under memory pressure using like "memhog", so it is starting to swap - "free" shows that used swap is non-zero. This will force the system to reclaim the file cache as you can see from /proc/meminfo that Active(file) and Inactive(file) start to decrease. Keep this pressure for a few days. 3) releasing the memory pressure, so file cache is increasing. Additional, the reproducer for BZ#617035 is a good regression test case for a corner case. There are also some good test cases upstream for this. http://lkml.org/lkml/2010/9/3/502 http://lkml.org/lkml/2010/8/30/226 Based on my testing, I've filed the bug 667707. For FUSE part, test using comment #4 and server works as normal. [root@ibm-hs21-01 fs_mark]# uname -a Linux ibm-hs21-01.rhts.eng.nay.redhat.com 2.6.18-232.el5 #1 SMP Mon Nov 15 16:01:45 EST 2010 x86_64 x86_64 x86_64 GNU/Linux [root@ibm-hs21-01 fs_mark]# mount ... sshfs#localhost:/mnt/gbfs on /MP1 type fuse (rw,nosuid,nodev,max_read=65536) [root@ibm-hs21-01 ~]# cat /proc/meminfo MemTotal: 16439360 kB MemFree: 15879776 kB Buffers: 64192 kB Cached: 285080 kB SwapCached: 0 kB Active: 200728 kB Inactive: 271460 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 16439360 kB LowFree: 15879776 kB SwapTotal: 18481144 kB SwapFree: 18481144 kB Dirty: 8 kB Writeback: 0 kB AnonPages: 122952 kB Mapped: 23680 kB Slab: 38740 kB PageTables: 8572 kB NFS_Unstable: 0 kB Bounce: 0 kB CommitLimit: 26700824 kB Committed_AS: 266244 kB VmallocTotal: 34359738367 kB VmallocUsed: 273904 kB VmallocChunk: 34359462763 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 Hugepagesize: 2048 kB [root@ibm-hs21-01 ~]# free -m total used free shared buffers cached Mem: 16054 546 15507 0 62 278 -/+ buffers/cache: 205 15848 Swap: 18047 0 18047 [root@ibm-hs21-01 ~]# cat /proc/swaps Filename Type Size Used Priority /dev/mapper/VolGroup00-LogVol01 partition 18481144 0 -1 run dd under memory pressure: [root@ibm-hs21-01 MP1]# while true;do memhog 15g; done [root@ibm-hs21-01 MP1]# dd if=/dev/zero of=test or [root@ibm-hs21-01 MP1]# for i in $(seq 1 10); do dd if=/dev/zero of=test$i bs=4096 count=2M; done "free" shows that used swap is non-zero and see from /proc/meminfo that Active(file) and Inactive(file) start to decrease: [root@ibm-hs21-01 ~]# free -m total used free shared buffers cached Mem: 16054 6652 9401 0 0 889 -/+ buffers/cache: 5761 10292 Swap: 18047 143 17904 [root@ibm-hs21-01 ~]# cat /proc/meminfo |grep ctive Active: 15387268 kB Inactive: 822796 kB [root@ibm-hs21-01 ~]# cat /proc/meminfo |grep ctive Active: 8511224 kB Inactive: 927640 kB [root@ibm-hs21-01 ~]# free -m total used free shared buffers cached Mem: 16054 9867 6186 0 0 470 -/+ buffers/cache: 9396 6657 Swap: 18047 160 17887 then run fs_mark under memory pressure for a long time, results shown normal like above: [root@ibm-hs21-01 fs_mark]# ./fs_mark -d /MP1 -D 256 -n 100000 -t 4 -s 20480 -F -S 0 -l fill.log I can't use memhog on i686 which shown "Function not implemented", but using fs_mark benchmark and dd to test for a long time, the server works normally. [root@hp-dl360g6-02 ~]# memhog 5000m mbind: Function not implemented get_mempolicy: Function not implemented [root@hp-dl360g6-02 ~]# memhog 8g membind Kernel doesn't support NUMA policy |