wcohen at redhat.com
Tue Sep 11 15:02:45 UTC 2007
Harald Hoyer wrote:
> Harald Hoyer schrieb:
>> 44.1% (1,6s) with /sbin/modprobe
> modprobe is parsing its configuration/dependency files every time it is
>> 12% (0.44s) with 60-net.rules
> I am sure 60-net.rules does not have to call
> /etc/sysconfig/network-scripts/net.hotplug for _every_ "net" event.
A while back I did some experiments with systemtap and found that modprobe was
doing a linear search through modules.deps:
I wrote a script that would prepend the modules that are actually used to the
beginning of modules.dep to reduce the average length of search. This reduced
the amount of data read (and time spent waiting for I/O) and slightly reduced
the time to boot the machine. Bootchart samples process state periodically.
Below is some of the data extracted from the bootchart samples:
all states D state
normal modules.dep 120 73
reordered modules.deps 63 27
Having to linearly through 250K of text in modules.dep each time a module is
loaded doesn't seem very efficient.
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