Re: [PATCH] convert udevsend/udevd to using datagram sockets

[Chris Friesen <chris_friesen@sympatico.ca>]

Kay Sievers wrote:

> You are talking about complexity, but what is about speed?
> 
> blocking daemon: time for i in `seq 1 100`; do SEQNUM=$i ACTION­d 
> DEVPATH=$i ./udevsend x; done real    0m1.175s user    0m0.054s sys 
> 0m0.081s
> 
> threading daemon: time for i in `seq 1 100`; do SEQNUM=$i ACTION­d 
> DEVPATH=$i ./udevsend x; done real    0m0.048s user    0m0.018s sys 
> 0m0.029s
> 
> I don't see what we get with the blocking I/O. It seems more like 
> personal taste than numbers. :)

Interesting numbers.  I instrumented the code in udevd using the x86 tsc
and got the following amounts of time to receive and queue all the
requests:

blocking recv() and datagrams: .13-.18 ms
threaded and streams: .05-.18 ms

I'm curious why my blocking recv() times are roughly on par with the
threaded numbers, while yours are much worse.

When I time how long it takes until all the requests are satisfied (i.e.
run_threads() has run 100 times), its 4-4.8 seconds either way--it
doesn't seem to matter.  Looks like this is due to the size of
EVENT_TIMEOUT_SEC more than anything else.

Note that these numbers are with a 1.6GHz Athlon XP, 2.6.1 kernel, and
linuxthreads rather than NPTL. (I know, I need to get NTPL going....)

I'm playing with a single-threaded version.  I'll let you know if it 
amounts to anything.

Chris





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