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devsk
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Joined: 24 Oct 2003
Posts: 2995
Location: Bay Area, CA
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 Posted: Thu Mar 08, 2007 7:41 am Post subject: |
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| energyman76b wrote: | | And 100mb is not much. Modern harddisks can deliver 100mb in less than 3 seconds. |
if all the files were sequentially placed, yes. Otherwise, no. | Code: | $ cd /usr/kde/3.5/lib
$ time for i in *.so*;do cat $i > /dev/null;done
real 0m3.380s
user 0m0.093s
sys 0m0.700s
$ sum=0
$ time for i in *.so*;do sum=$((sum+`/bin/ls -al $i | awk '{print $5}'`));done
$ echo $sum
68815733
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i.e. ~70MBytes on a RAID0 of WD74GB raptors using Reiser4 takes 3.4 seconds to load in memory. Sequential B/W has nothing to do with how fast you read scattered files. And mind you I am inside KDE and many of these libraries were in RAM when I typed above commands from konsole. You can easily double or even triple that time to just account for RAID0, raptors' low latency and cache effect.
So, if I am loading 10 kde executables at startup and each doing 25,000 relocations (all 25,000 taking 0.1 second on my machine, as per LD debug) I add only 1 (10 * 0.1) seconds to my startup time without prelink. But 100MB extra and I am adding 5 seconds extra with prelink. So, where's the math?
Trust me: disk IO is still the most of the time during startup (and more so with faster processors), and yes, relocations do become a bigger chunk on older processors like P2 or P3.
PS: Don't get confused/misled by LD_DEBUG=statistics. clock cycles for library load are low because you don't spend any cpu cycles while waiting for the IO: you are de-scheduled by the kernel. of course, the clock cycles are needed for relocations and relocations don't make you wait on IO, hence making its %age larger. |
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energyman76b
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Joined: 26 Mar 2003
Posts: 2048
Location: Germany
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| Posted: Thu Mar 08, 2007 7:24 pm Post subject: |
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Well, I believe what I measured.
And even with my actual system (specs in the sig), KDE starts a lot faster. And KDE-apps too. Believe me. I sat there with a stop watch, and did a lot of measurements. And it was always the same. KDE starts in a lot less time (between half and 90% less), Konqueror starts a lot faster (several seconds faster), kmail,....
I did it back in 2004, and I did it with each reinstallation... and the results were always the same.
So something is still flawed...
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Study finds stunning lack of racial, gender, and economic diversity among middle-class white males
I identify as a dirty penismensch. |
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1ino1eum_4the_win
Tux's lil' helper
Joined: 07 May 2006
Posts: 92
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| Posted: Mon Mar 12, 2007 7:15 am Post subject: |
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| I just wonder, why the wiki and the howto is not updated with this new informations ? |
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BMintern
n00b
Joined: 12 Mar 2007
Posts: 22
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| Posted: Sat Jun 21, 2008 12:27 am Post subject: |
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| I am running GCC 4.3.1 on an Athlon 64 X2 with 1 GB ram. Would prelinking offer me any advantages, or does this no longer apply? |
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energyman76b
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Joined: 26 Mar 2003
Posts: 2048
Location: Germany
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| Posted: Sat Jun 21, 2008 4:13 am Post subject: |
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| BMintern wrote: | | I am running GCC 4.3.1 on an Athlon 64 X2 with 1 GB ram. Would prelinking offer me any advantages, |
yes
| BMintern wrote: |
or does this no longer apply? |
no
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Study finds stunning lack of racial, gender, and economic diversity among middle-class white males
I identify as a dirty penismensch. |
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AxeZn
n00b
Joined: 30 Sep 2011
Posts: 1
Location: Quebec, Canada
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| Posted: Fri Sep 30, 2011 7:14 am Post subject: Wow. |
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Guenther, your "Gentoo Love" post (the one explaining your move from game-loader-OS to Gentoo) rang an echo bell in me. I've been through this as well (I tried Knoppix, mandrake, Mandriva, Xbox-Linux, Wiinux (Lenny on Nintendo Wii), [K,X,U]buntu, Linux Mint, Debian, Gentoo, and this week Arch Linux. My favorites are and Gentoo, Arch and Debian), except for the programming part. Gentoo is a pure geek dream for me, where you actually are told what you are doing, why, and if you don't like it, you have the choice to do it otherwise, and even in that case there will be someone to help you. As example, I managed to compile a third-party Second Life viewer today and someone guided me finding the issue, installing Gentoo with my world on his system and working it through with me. we had to recompile the library the viewer was providing only statically due to a design fault where it was using libpango linked dynamically to libfreetype, but freetype was only provided as a static library, thus forcibly using the system one, which of course wasn't using the depreciated functions the viewer needed (phew! I said it all!).. /brainfryingexplanation
Said shortly, I love Gentoo. I also learn a lot, and I love learning how things works. I'm currently using a 32-bit gentoo for the simple reason that I stayed away from the 64-bit version of Linux because gstreamer issues with Second Life. I'm really enthusiast to make the move to 64-bit, though, as my system would probably gain a lot. Specs being:
CPU: AMD Phenom(tm) II X6 1055T Processor (2809 MHz)
Memory: 12171 MB
OS Version: Linux 3.0.4-ck #2 SMP PREEMPT Wed Sep 28 06:22:48 EDT 2011 i686
Graphics Card Vendor: NVIDIA Corporation
Graphics Card: GeForce GTX 260/PCI/SSE2/3DNOW!
OpenGL Version: 3.3.0 NVIDIA 275.09.07
I'm quite sure I can get it working a lot better than I'm used to because, honestly, the last time I used KDE was on debian and I saw Win7 run faster than that.
Go Gentoo!
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Mon Apr 30 02:05:18 EDT 2012
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