Re: Hardening patch
Hi Guillem,
On Tue, 13 Sep 2011, Guillem Jover wrote:
> Well, the concerns were coming from first-hand experience from working
> on ARM systems, otherwise I'd not have commented. Specifically on
> Maemo the startup time was so bad for UI apps, we created maemo-launcher
> just to improve it.
Ok, but I'm not yet able to read into minds :-)
> I installed iceweasel on an ARM system (Thecus N2100), w/o X forwarding,
> and no user profile, so it just stops when it's not able to find the
> DISPLAY, but that should be good enough to get timings close to just the
> startup relocation times, which is what the ld.so stats show on amd64
> for example. Caches flushed on each iteration, which were pretty
> consistent, I've included two different ones for each:
I did the same on my eSATA SheevaPlug (armel too) and I don't get the same
results than you.
rhertzog@nas:~$ echo 3 | sudo sponge /proc/sys/vm/drop_caches
rhertzog@nas:~$ time LD_DEBUG=statistics MOZ_NO_REMOTE=1 iceweasel -ProfileManager
[...]
Error: no display specified
10941:
10941: runtime linker statistics:
10941: final number of relocations: 3306
10941: final number of relocations from cache: 26441
real 0m1.771s
user 0m0.100s
sys 0m0.090s
rhertzog@nas:~$ echo 3 | sudo sponge /proc/sys/vm/drop_caches
rhertzog@nas:~$ time LD_DEBUG=statistics MOZ_NO_REMOTE=1 iceweasel -ProfileManager
[...]
Error: no display specified
10948:
10948: runtime linker statistics:
10948: final number of relocations: 3306
10948: final number of relocations from cache: 26441
real 0m1.905s
user 0m0.110s
sys 0m0.080s
rhertzog@nas:~$ echo 3 | sudo sponge /proc/sys/vm/drop_caches
rhertzog@nas:~$ time LD_BIND_NOW=1 LD_DEBUG=statistics MOZ_NO_REMOTE=1 iceweasel -ProfileManager
[...]
Error: no display specified
11034:
11034: runtime linker statistics:
11034: final number of relocations: 17420
11034: final number of relocations from cache: 26441
real 0m1.771s
user 0m0.230s
sys 0m0.140s
rhertzog@nas:~$ echo 3 | sudo sponge /proc/sys/vm/drop_caches
rhertzog@nas:~$ time LD_BIND_NOW=1 LD_DEBUG=statistics MOZ_NO_REMOTE=1 iceweasel -ProfileManager
[...]
Error: no display specified
11041:
11041: runtime linker statistics:
11041: final number of relocations: 17420
11041: final number of relocations from cache: 26441
real 0m2.056s
user 0m0.270s
sys 0m0.100s
> As it can bee seen the difference is pretty significant.
As it can be seen, the difference is not something that affects
all armel machines in the same way.
I did 10 run of each, dropped the biggest value and did the mean
value on the rest:
- bind lazy: 1.842s
- bind now: 1.910s
Difference: +3,6 %
I'm using the plain Debian kernel and all squeeze packages.
$ uname -a
Linux nas 2.6.32-5-kirkwood #1 Wed Jan 12 15:27:07 UTC 2011 armv5tel GNU/Linux
> > Feel free to change it if you think it's better that way. I'm not attached
> > to it.
>
> I'm changing it now on my local tree, will be included in my next
> push.
Given my test, I'm not convinced it's the right course of action.
I did the same test on my i386 setup and I got this:
- bind lazy: 0.320s
- bind now: 0.330s
Difference: +3,1 %
At the very least, we could keep it enabled for i386/amd64, no ?
Cheers,
--
Raphaël Hertzog ◈ Debian Developer
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▶ http://RaphaelHertzog.fr (Français)
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