Bug 761884 (GLUSTER-152) - libglusterfsclient: DHT workaround is a major performance bottleneck
Summary: libglusterfsclient: DHT workaround is a major performance bottleneck
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: GLUSTER-152
Product: GlusterFS
Classification: Community
Component: libglusterfsclient
Version: mainline
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Shehjar Tikoo
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Blocks:
TreeView+ depends on / blocked
 
Reported: 2009-07-19 08:49 UTC by Shehjar Tikoo
Modified: 2009-08-12 06:03 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
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Regression: RTNR
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Description Shehjar Tikoo 2009-07-19 05:50:45 UTC 
BTW, Avati also observed performance increase from 2-5 MiB/s with the problem, to around 40 MiB/s with a temporary fix he introduced on a customer setup.
Comment 1 Shehjar Tikoo 2009-07-19 05:54:49 UTC 
Proposed patches:
release-2.0: http://patches.gluster.com/patch/784/
mainline: http://patches.gluster.com/patch/785/
Comment 2 Shehjar Tikoo 2009-07-19 08:49:23 UTC 
As reported by Avati.

In libgf_client_path_lookup, the workaround for DHT requirement for a 
lookup on / needs to be done only once when the xlator graph is inited.

Doing it on every path's lookup results in a major performance penalty when using distribute subvolumes upwards of 16, because a lookup for the root needs to be sent on every subvolume.
Comment 3 Anand Avati 2009-07-20 18:29:29 UTC 
PATCH: http://patches.gluster.com/patch/785 in master (libglusterfsclient: Move DHT root-lookup workaround to init)
Comment 4 Anand Avati 2009-07-20 18:29:40 UTC 
PATCH: http://patches.gluster.com/patch/784 in release-2.0 (libglusterfsclient: Move DHT root-lookup workaround to init)
Comment 5 Shehjar Tikoo 2009-07-23 09:48:39 UTC 
Committed to repo:
Release 2.0: http://git.savannah.gnu.org/cgit/gluster.git/commit/?h=release-2.0&id=7b90b90780d3bb5a1b4a1c060fac1d2c4eb2a8dc

Mainline: http://git.savannah.gnu.org/cgit/gluster.git/commit/?id=a12f332cff050db3aa3905436158cbd339fa6963
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