[SOLVED] Silly question about System.map in Slackware tree

Miranden · 03-19-2014, 02:54 PM

Hi,

I am planning to go back to an old kernel on my laptop running Slackware64-14.1, and I wanted to use one of the ones from Slackware 14 instead of compiling my own. In the Slackbook, it says this:

Quote:

4.2.1 The /kernels Directory on the Slackware CD-ROM

The precompiled Slackware kernels are available in the /kernels directory on the Slackware CD-ROM or on the FTP site in the main Slackware directory. The available kernels change as new releases are made, so the documentation in that directory is always the authoritative source. The /kernels directory has subdirectories for each kernel available. The subdirectories have the same name as their accompanying boot disk. In each subdirectory you will find the following files:
File Purpose
System.map The system map file for this kernel
bzImage The actual kernel image
config The source configuration file for this kernel

To use a kernel, copy the System.map and config files to your /boot directory and copy the kernel image to /boot/vmlinuz. Run /sbin/lilo(8) to install LILO for the new kernel, and then reboot your system. That's all there is to installing a new kernel.

So that sounds easy enough. However, I notice that the System.map in the kernels directory of the 14.0 tree is compressed, so it is System.map.gz. So I should uncompress it, right? Since the Slackbook doesn't mention that, I thought I'd better ask . . . I'm not quite sure how the system reads this file or what it does with it.

Told you it was a silly question.

Didier Spaier · 03-19-2014, 05:41 PM

Yes, you should uncompress it (that's done by script SeTkernel of Slackware installer, for instance).

Furthermore System.map is mostly useful for kernel debugging purposes, and you won't probably need it for that.

It was used by some drivers also some years ago, but I'm not sure that's still true.

Miranden · 03-19-2014, 06:03 PM

Okay thanks, I will then. Maybe I won't need it anyway, but I might as well put it in there just in case.

Thanks for the information!

TobiSGD · 03-19-2014, 06:40 PM

Just out of curiosity, why would you use an older kernel?

Miranden · 03-19-2014, 08:04 PM

Well, actually the problem I'm having may not be kernel related (in fact it probably isn't), but recently I've been having some performance issues on my laptop. I am noticing the cpu is always running above 30% with just a browser and a tab or two open (I run i3, so it's not a WM/DE issue), and RAM usage is over 20%. The fan is always on high trying to cool things down. Firefox hangs a lot, and sometimes the cpu usage will go up to 90 percent or so and everything will freeze.

The laptop is an ultrabook so it doesn't have the best specs, but it's only a year old, and it has a 1.7 GHz Ivy Bridge and 4 GB of RAM, which I thought should be good enough to prevent that kind of resource shortfall. When I run top it always shows Firefox eating the majority of resources, so I think it may actually be a Firefox issue.

Anyway, going back to the 14.0 kernel is just something I wanted to try to see what happened. Everything was working perfectly back then. Just a few months ago I rarely went above 10 percent on anything, and the fan basically stayed off. Even if it isn't a kernel problem, I wanted to know how to switch kernels like this anyway, because it is an easy thing that I thought I should know how to do. I've built my own kernel before, but I've never just grabbed a built one and put it in.

I will have to wait and see what happens.

moisespedro · 03-19-2014, 08:43 PM

Firefox is always hungry, he always needs more RAM.

Miranden · 03-19-2014, 09:20 PM

Quote:

Originally Posted by moisespedro

Firefox is always hungry, he always needs more RAM.

Firefox shouldn't be using 90% of resources and freezing the system. And like I said, this is a new issue.

Whatever this is, it is not normal Firefox functioning.

Anyway, I just wanted to test performance under another kernel to see what happens. If it doesn't work, then I'll file a bug report or switch to Opera.

TobiSGD · 03-19-2014, 09:26 PM

For an Ivybridge CPU I would rather recommend to use the latest kernel and make sure that your cpufreq governor is set to pstate. IIRC, there were some regressions in the 3.10 kernel with power-management and performance on that CPU.
For testing purposes trying the older 3.2 kernel is an option, for 24/7 use on a newer Intel CPU it is definitely not.

moisespedro · 03-19-2014, 09:44 PM

Quote:

Originally Posted by Miranden

Firefox shouldn't be using 90% of resources and freezing the system. And like I said, this is a new issue.

Whatever this is, it is not normal Firefox functioning.

Anyway, I just wanted to test performance under another kernel to see what happens. If it doesn't work, then I'll file a bug report or switch to Opera.

Here it uses something like 40% CPU and 20% RAM, yeah it sucks but not as bad as yours.

genss · 03-20-2014, 12:08 PM

Quote:

Originally Posted by Miranden

Firefox shouldn't be using 90% of resources and freezing the system. And like I said, this is a new issue.

Whatever this is, it is not normal Firefox functioning.

go to about:memory and check

some week ago i had a tab open and in that tab was that facebook thingy
i think it was using my computer as a click farm since it used 700mb memory(many instances) and a fair part in cpu
(didn't bother confirming tbh, its adblocked now)

qweasd · 03-20-2014, 01:04 PM

Quote:

Originally Posted by Miranden

Ivy Bridge <snip> going back to the 14.0 kernel

That's kernel 3.2.29? Be warned, Ivy Bridge driver was terribly broken until 3.3. Depending on how heavily I used the graphics, it would mess up the screen and lock up the computer dead after 1-3 hours.

Code:

Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)

Is that Ivy Bridge? I can't even tell

Miranden · 03-21-2014, 10:58 AM

Quote:

Originally Posted by qweasd

That's kernel 3.2.29? Be warned, Ivy Bridge driver was terribly broken until 3.3. Depending on how heavily I used the graphics, it would mess up the screen and lock up the computer dead after 1-3 hours.

Code:

Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)

Is that Ivy Bridge? I can't even tell

I'm not sure. Try 'less /proc/cpuinfo'.

Thanks for letting me know, I wasn't aware of the Ivy Bridge driver issue. I think mine was working perfectly under that kernel, though . . . wait, I've had this computer running Slackware64 since May of 2013, when I bought it. But, I forgot I was running -current back then. So I will need to check to see when the kernel was changed to see what was working well. I guess I'm just running too many Slack machines to keep things straight.

Thanks again.

genss: about:memory shows one negative value in memory usage (for canvas-2d-pixel-bytes, used for 2D canvases), which means an error in memory reporting. But I'm not sure that could cause this issue. I think I will stick to my original plan and test it with the other kernel before investigating further. I was busy yesterday and put it off, so I'm doing it now.

genss · 03-21-2014, 11:53 AM

Quote:

Originally Posted by Miranden

genss: about:memory shows one negative value in memory usage (for canvas-2d-pixel-bytes, used for 2D canvases), which means an error in memory reporting. But I'm not sure that could cause this issue. I think I will stick to my original plan and test it with the other kernel before investigating further. I was busy yesterday and put it off, so I'm doing it now.

just a stab
go to about:config and make layers.acceleration.disabled true

Miranden · 03-21-2014, 02:13 PM

Okay, that was really weird. I found out the kernel I was using back when I first installed -current on this machine was 3.8.8. But, since I had already downloaded the built version of 3.2.29, I thought I would boot it up just for kicks. I found that it didn't have the same interface for my keyboard backlight, and for some reason I could not start x as my normal user. I logged into XFCE as root, and from what I could tell the CPU and memory looked a bit better, but my normal user uses i3, which I don't have set up as root, so it was not a fair comparison (of course, I would expect i3 to be lighter weight, but still, difference in testing is bad). I couldn't really tell though, because I usually judge memory and CPU usage by the the conky I build into i3 status, which was absent.

I thought I would go back to the 3.10.17 kernel for a bit so that I could adjust my backlight and maybe build another kernel a bit more recent. When I did, I still could not start x as a non-root user. I got an error that said .Xauthority was not writable and changes would be ignored. I deleted my ~/.Xauthority file and rebooted. No change. Checked disk space. I had plenty. So I ran xwmcnfig and found that even though I use i3, it was set on XFCE, which is root's default environment. I changed it back to i3. This fixed X, and I started up i3.

So at this point, I thought I should be back where I started. I had removed the simlinks to the System.map, the new kernel config, and the new kernel image and put them back the way they were. Everything was as it had been before. But suddenly, my CPU and RAM usage are back to normal! CPU hovers around 1 - 3 percent with 3 desktops on i3, running Firefox (7 tabs open), Open Office, Thunar, and a terminal. Everything is working great!

I don't know what happened. That was just odd.