Re: SoC idea: desktop file cache

[Adrien Bustany <abustany gnome org>]

Le Wed, 30 Mar 2011 15:46:03 -0300,
Juan Pablo Ugarte <juanpablougarte gmail com> a écrit :

> Hi guys, I had to give DBUS a try, so I went and modified the gdbus
> test to get some numbers.
> 
> Running a thousand transactions takes about 1.5 seconds and there is
> no big difference if the we transfer 50 bytes or 4 kbytes.

This is probably due to the fact that the daemon writes data in chunks
of 4kb... So you probably have to batch in 4kb chunks on app side
(when it's possible).

Note that for big data transfers, using FD passing and a socket is
quite faster, but probably overkill here.

> 
> Here is the output of the test on my machine (Athlon 64 x2 5600+ with
> DDR2 ram)
> 
> Took 3.020150 seconds to run 2000 iterations of 51 bytes each =
> 33773.156962 bytes/s
> 
> Took 3.193050 seconds to run 2000 iterations of 4079 bytes each =
> 2554923.975509 bytes/s
> 
> Took 0.081563 seconds to run 2 iterations of 1007029 bytes each =
> 24693280.041195 bytes/s
> 
> Took 0.752203 seconds to run 20 iterations of 1007029 bytes each =
> 26775458.220720 bytes/s
> 
> I assume here the bottle neck is the context switch between both
> server and client.
> 
> So I think DBus speed wont be an issue transferring desktop entries
> to a client.
> 
> my 2 cents
> 
> Juan Pablo