Hi David,
David Sommerseth wrote:
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On 15/03/10 16:29, Jan Just Keijser wrote:
More tests, this time with 'oprofile' : here's a recap:
- nothing changed on the server side:
openvpn --ifconfig 10.222.0.1 10.222.0.2 --dev tun --secret secret.key
--cipher none
- upgraded to kernel 2.6.32.9-70.fc12.x86_64 on my laptop
- selinux is disabled
- installed the debuginfo rpms to get a 'vmlinux'
- configure the oprofile deamon using
opcontrol
--vmlinux=/usr/lib/debug/lib/modules/2.6.32.9-70.fc12.x86_64/vmlinux
- now start it, reset the statistics, start openvpn
opcontrol --start
opcontrol --reset
./openvpn --ifconfig 10.222.0.2 10.222.0.1 --dev tun --secret
secret.key --remote kudde.nikhef.nl --cipher none
- download a file using 'nc' (this maxes out my 100 Mbps LAN at roughly
11 MB/s)
- get the statistics
opcontrol --dump
opreport -l > stats
Thanks a lot! This is way cool! It just strikes me that you probably
should play with ftrace instead of oprofile. It's better and got a
lower overhead than oprofile, afaik.
<http://lwn.net/Articles/322666/>
(btw. with an ftrace enabled kernel, it's even available on embedded
devices. You only need 'mount', 'echo' and 'cat' to interact with ftrace
... even though Steven Rostedt is working on a GUI for ftrace, called
kernelshark)
With such new kernel, there's also the perf tool.
<http://perf.wiki.kernel.org/index.php/Main_Page>
In both of these tools you have something called callgraph, iirc. And
with that you see which function is calling which function and the
amount of time each step used.
I'll ask some people who's been involved in both ftrace and perf for
some better pointers!
your wish is my command ;-) :
actually, 'perf' is a lot easier to use then opcontrol/opreport. I ran
perf record -g -f -- ./openvpn ..................
perf report --call-graph > perf.data-20100316
At
http://www.nikhef.nl/~janjust/openvpn/perf.callgraph-20100316.gz
you will find the callgraph for a 512 MB file copy ; the rest is
identical to the previous tests.
share and enjoy,
JJK / Jan Just Keijser
