Jump to content

Performance tuning - which syctl params to tweak?


Recommended Posts

I once read (I cannot find the link anymore) that there were only

3 or 4 parameters "in the kernel configuration?/ kernel parameters", excluding scheduling,

worth tinkering with to improve linux performance.

I think they were mostly to do with how long "the RAM cache"?

keeps information, or cycle it, before dumping it to the HD swap.

And there were 2 more things of the like, to do with memory allocation

or time things are allowed to stay in memory AFAI can remember.

These were maybe in sysctl; I remember that the article was talking

about editing a file in /etc (and I think it was a redhat example)

 

Does anybody know what I may be talking about above? Thanks.

Only a human brain can answer my vague question...

 

As a home user hobbyist I have no particular goals or target,

nor good benchmarking at hand (a sarcheck like software for home user would be nice though).

I just want to know where these parameters are, what they are, by curiosity.

I read http://www.linuxforums.org/desktop/linux_p...nce_tuning.html

 

I have used hdparm, bonnie, nice, removed services etc.

I suppose I could include kolivas kernel patches

or urpmiload a mutimedia kernel. This is not the question really.

Qemu tells me to increase the "interupt frequency" to 1024 instead of 64

(when I recompiled the kernel I thought I removed a lot of modules and set this

up to 1024 Hz? apparently not).

 

Having used vector linux, I really do get the feeling that there is room for tweaking...

So it makes me curious

Edited by emmanuel_uk
Link to comment
Share on other sites

The ones I tend to do are editing /etc/inittab and commenting out the tty's I don't need, normally 3,4,5 and 6. Then editing /etc/sysctl.conf and adding:

 

vm.swappiness = 10

 

and then sysctl -p to activate it, or reboot.

Link to comment
Share on other sites

Ian, thanks ever so much, you are bang on, this was the one swappiness

 

The other one that was described in that paper were possibly one of these (a dirty trick!)

vm.nr_pdflush_threads = 2

vm.dirty_expire_centisecs = 2999

vm.dirty_writeback_centisecs = 499

vm.dirty_ratio = 40

vm.dirty_background_ratio = 10

 

Maybe there was /proc/sys/vm/vfs_cache_pressure as well but it is

not there on my PC

 

I stumbled on

"System Tuning Info for Linux Servers"

http://people.redhat.com/alikins/system_tuning.html

 

Can do a lot of reading by cross-referencing keywords now :-)

Link to comment
Share on other sites

Solved, but wanted to add some links to relevant optimisation,

system tuning, system performance...

 

The reference I suppose

http://members.optusnet.com.au/ckolivas/kernel/

 

Not updated recently but he knows what he is talking about!

http://people.redhat.com/alikins/system_tuning.html

 

About the topic

http://en.wikipedia.org/wiki/Virtual_memor...perating_system

 

Disapointing

http://www.performancewiki.com/linux-tuning.html#Kernel

 

Listing lots of things but one need to come to own conclusions

http://webrink.blogspot.com/2006/01/perfor...ux-servers.html

 

the original ideas of tweaking I learned from a rather old file

http://tldp.org/LDP/solrhe/Securing-Optimi...dition-v1.3.pdf

this was for Red Hat Linux 6.2

Edited by emmanuel_uk
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...