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IDProjectCategoryView StatusLast Update
0017904CentOS-8dbuspublic2020-12-03 02:32
Reporternoeleon Assigned To 
Status newResolutionopen 
Product Version8.2.2004 
Summary0017904: High dbus-daemon CPU
DescriptionWe have a system that does a very large number of user and group lookups.

Since moving to CentOS 8 that dbus-daemon will saturate the CPU when there is a large number of these lookups occuring.

dbus-monitor --system will show a repeaded stream of:

sig 1606662078.428231 5237199 org.freedesktop.DBus <none> /org/freedesktop/DBus org.freedesktop.DBus NameOwnerChanged
sig 1606662078.428237 2 org.freedesktop.DBus :1.2618601 /org/freedesktop/DBus org.freedesktop.DBus NameAcquired
mc 1606662078.428475 2 :1.2618601 org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager GetDynamicUsers
mr 1606662078.428657 2622380 :1.2 :1.2618601 2
sig 1606662078.428829 3467 org.freedesktop.DBus :1.2618601 /org/freedesktop/DBus org.freedesktop.DBus NameLost
sig 1606662078.428839 5237200 org.freedesktop.DBus <none> /org/freedesktop/DBus org.freedesktop.DBus NameOwnerChanged
mc 1606662078.429110 1 :1.2618602 org.freedesktop.DBus /org/freedesktop/DBus org.freedesktop.DBus Hello
mr 1606662078.429119 1 org.freedesktop.DBus :1.2618602 1
sig 1606662078.429124 5237201 org.freedesktop.DBus <none> /org/freedesktop/DBus org.freedesktop.DBus NameOwnerChanged
sig 1606662078.429130 2 org.freedesktop.DBus :1.2618602 /org/freedesktop/DBus org.freedesktop.DBus NameAcquired
mc 1606662078.429254 2 :1.2618602 org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager GetDynamicUsers
mr 1606662078.429324 2622381 :1.2 :1.2618602 2

We can comlpetely alleviate the load by removing 'systemd' from 'group:, 'passwd:' entries in /etc/nsswitch.conf, this removes and of the DynamicUser= functionality though and possibly other functionality?

Is there a better solution to removing this functionality or is there a bug within dbus whereby GetDynamicUser which could be optimized.

Steps To ReproduceAny program that makes heavy use of getpwnam() or getgrouplist()
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Issue History

Date Modified Username Field Change
2020-12-03 02:32 noeleon New Issue