Computer feels slow and laggy

evert_ · 2010-10-07 12:18:13

The description is a bit vague, but it's hard to describe the exact problem. I hope I'm posting the correct sub forum.

I'll start with giving all relevant system information I can think of:

root@linux ~ % uname -a
Linux linux 2.6.35-ARCH #1 SMP PREEMPT Wed Sep 29 08:45:18 CEST 2010 x86_64 Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz GenuineIntel GNU/Linux

root@linux ~ % free -m
             total       used       free     shared    buffers     cached
Mem:          2008       1993         15          0         45       1401
-/+ buffers/cache:        546       1462
Swap:         2859          0       2859

root@linux ~ % cat /proc/mdstat 
Personalities : [raid6] [raid5] [raid4] [raid1] 
md0 : active raid1 sda1[0] sdc1[2] sdb1[1]
      248896 blocks [3/3] [UUU]
      
md1 : active raid5 sda2[0] sdc2[2] sdb2[1]
      976269824 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

root@linux ~ % uptime 
 14:03:42 up  3:09,  1 user,  load average: 2.62, 1.69, 1.50

root@linux ~ % df -h
Filesystem            Size  Used Avail Use% Mounted on
udev                   10M  164K  9.9M   2% /dev
/dev/lvm/root          19G  8.4G  9.1G  48% /
shm                  1005M     0 1005M   0% /dev/shm
/dev/md0              236M   19M  205M   9% /boot
/dev/mapper/lvm-home  896G  796G   55G  94% /home

root@linux ~ % pvdisplay 
  --- Physical volume ---
  PV Name               /dev/md1
  VG Name               lvm
  PV Size               931.04 GiB / not usable 512.00 KiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              238347
  Free PE               0
  Allocated PE          238347
  PV UUID               ife6Aj-C0ea-JAAP-GcZL-KG3Q-qb5l-rFxkXk
   
root@linux ~ % vgdisplay 
  --- Volume group ---
  VG Name               lvm
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               931.04 GiB
  PE Size               4.00 MiB
  Total PE              238347
  Alloc PE / Size       238347 / 931.04 GiB
  Free  PE / Size       0 / 0   
  VG UUID               5U3AA7-smC5-Fp0T-e0KL-dW3d-D3i7-oesgsz
   
root@linux ~ % lvdisplay 
  --- Logical volume ---
  LV Name                /dev/lvm/root
  VG Name                lvm
  LV UUID                gRT6LU-1mdJ-PtK2-dNvX-jnfm-w2St-hv100J
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                18.62 GiB
  Current LE             4768
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     512
  Block device           254:0
   
  --- Logical volume ---
  LV Name                /dev/lvm/swap
  VG Name                lvm
  LV UUID                ITWVuo-vLZz-dq2C-zXQ5-1058-lisO-sto2Z7
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                2.79 GiB
  Current LE             715
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     512
  Block device           254:1
   
  --- Logical volume ---
  LV Name                /dev/lvm/home
  VG Name                lvm
  LV UUID                rwSEga-FcS3-jrpV-DzWX-ETpO-03Yh-4X828X
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                909.62 GiB
  Current LE             232864
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     512
  Block device           254:2

               +                
               #                OS: Arch Linux x86_64
              ###               Hostname: linux
             #####              Kernel: 2.6.35-ARCH
             ######             Uptime: 3:11
            ; #####;            Window Manager: DWM
           +##.#####            Desktop Environment: None found
          +##########           Packages: 558
         #############;         RAM: 548 MB / 2008 MB
        ###############+        CPU: Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz
       #######   #######        Shell: Zsh
     .######;     ;###;`".      Root FS: 8.4G / 19G (ext4)
    .#######;     ;#####.       
    #########.   .########`     
   ######'           '######    
  ;####                 ####;   
  ##'                     '##   
 #'                         `#

If there is any other system information needed, please don't hesitate to ask.

Now the problem: well it's just general 'latency' and slowness of the computer, affecting nearly all applications. On a fresh boot when I try to login on the TTY I'm able to type half of the password before it gives me the prompt for it. Same when doing a 'su' in a urxvt.

Also, firefox is being very slow and unresponsive. Changing tabs goes slow, even typing text here right now lags from time to time (me typing faster then firefox showing the text). Running applications like SABnzbd makes all things go from bad to worse.

As you probably can understand, working on a computer which is feeling very laggy isn't very amusing. I hope there would be some pointers on how to get it working fast(er).

lilsirecho · 2010-10-07 16:35:25

The indication of 19mb of free memory suggests that you have saturated the available memory.

Perhaps you can determine what is causing the excessive use of memory and take steps to correct the high level of memory use which causes use of swap(slowdown).

machoo02 · 2010-10-07 17:00:10

The important line on there is the +/- buffers/cache...evert_ still has ~1.5 GB of ram available, so this is not the problem. Neither is swap (which shows a value of 0 under used). It sounds like something is hitting the processor hard, perhaps something going on in the background. What does the output of top/htop look like after a while?

Last edited by machoo02 (2010-10-07 17:00:21)

Zom · 2010-10-07 17:16:24

Perhaps it's related to this:

Kernel 2.6.35 I/O congestion

mangust · 2010-10-07 17:23:58

consider this question: are you comfortable with 64bit system on 2GB of RAM? Once I've tried 64bit ArchLinux on my 1GB RAM: it worked, but running more than one program made the system slow. However it might be not your case. Investigate what Zom and machoo02 suggested.

TigTex · 2010-10-07 17:35:51

root@linux ~ % uptime 
 14:03:42 up  3:09,  1 user,  load average: 2.62, 1.69, 1.50

Your pc is running under heavy load... Check "top" or "htop" to see if there is anything using all the cpu resources. If not, it's the kernel 2.6.35 bug.... and make sure your pc isn't overheating

Last edited by TigTex (2010-10-07 17:42:41)

evert_ · 2010-10-07 18:07:52

Thanks for the suggestions so far .

I'm having indeed more then a 1gb free ram and no swap is used, so that's not causing the problem. At the moment that I checked the load to post it over here SABnzbd was actively downloading, so that caused some extra load. But even now, my computer semi-idle (read: only some terminals/firefox) active it still gives me:

 20:03:18 up  9:09,  1 user,  load average: 0.67, 0.63, 0.72

When I look into (h)top there is no process using excessive amounts of cpu. It seems relative idle, except for firefox popping up from time to time using 10% cpu for half a second. Nothing what should or could cause such a load, so it seems I'm 'affected' by the 2.6.35 bug?

I'm only posting this now because I started to get really annoyed by it (and it might have gotten worse with the .35 bug), but the system is feeling slow for some time now.

lilsirecho · 2010-10-07 19:14:52

Perhaps the problem is related to the cpu cache...is it a shared cache?

TigTex · 2010-10-07 19:23:11

Are you having high hard disk activity? (use iotop to see that).
The load average is a little high at idle, but that doesn't seem to be cause of that slowness...

There are some workarounds here https://bbs.archlinux.org/viewtopic.php?id=103346 for the kernel 2.6.35 "bug".

evert_ · 2010-10-08 09:34:00

There is no high hdd activity.

It seems I'm not affected by the .35 'bug', after login on the tty my load drops to 0.0x after a few minutes, so that's good I guess.

I really don't understand what makes my pc feel so laggy and unresponsive. At this very moment I'm running firefox (few tabs open), sabnzbd (limited to 500kb/s), mpd and irssi.

Still the load is way over 1 again, which just shouldn't be with only so few applications running. And it shouldn't make typing in firefox a hell because of the latency showing up every few words.

I know some people who run about the same programs with as much cpu power and they don't have any problems with it. So there definitely is something wrong, but only what?

lilsirecho · 2010-10-08 15:38:52

Perhaps your system slowness is related to the slowness introduced by raid5 which slows writes.

Many googles on the subject. It seems that performance is not enhanced with raid of any type according to some of the googles.

Just another possibility...................

DIDI2002 · 2010-10-08 17:19:03

My laptop also felt "slow" although nothing was in top / iotop / ps. I tried using kernel26-pf with BFS and BFQ enabled, and somehow this resolved the issue completely.

720p h264 on kernel26 feels sluggish...720p on kernel26-pf runs perfectly smooth
Wouldn't hurt to try, I guess:

[pfkernel]
Server = http://dl.dropbox.com/u/11734958/i686

evert_ · 2010-10-09 09:08:33

I'm not wanting or willing to replace my raid5 with something else. I do like the 'safety' against a broken harddisk. I know raid5 is not a backup (i've got the most import in a good backup, not at home). If i do the random write tests it indeed scores very very bad. My filesystem is relative full (only few gb's empty), this might cause the write speed to slow down even more.

I've never tried any 'special' kernel, but I'll give it a shot. I'd rather not download kernel files from your dropbox (url broken btw), but from a more reliable source. Let's hope some other sheduler will fix the problems .

Cotton · 2010-10-09 09:25:47

evert_ wrote:

I... My filesystem is relative full (only few gb's empty), this might cause the write speed to slow down even more...

Almost certainly.
I've had similar problems in the past when free disk space (<1% of total) has been running low. Even if that 1% is several GBs.
Never did work out the problem. No apparent background tasks, no low RAM, no excessive swap usage.

One thing that might be worth doing is to run memtest to check your RAM is not playing up.

TigTex · 2010-10-09 15:19:05

I would also check your hardware for problems...
Check your temperatures, power supply voltages, memtest your rams, check your hdd smart status, test your system stability and try to free some space on your root filesystem. And possibly update your bios and see if everything is at stock speed and voltage (cpu, ram, ...)
hdparm -tT /dev/sdX is a good and fast way to see if your hdd's are performing well.

If the problem is not hardware, well, at least it's not the hardware! kernel 2.6.36 is almost here also, maybe it solves some problems

Cotton · 2010-10-09 15:43:46

TigTex wrote:

... kernel 2.6.36 is almost here also, maybe it solves some problems

Disk speed probably won't be one of them!:

http://www.phoronix.com/scan.php?page=a … trfs&num=1

Arch Linux

#1 2010-10-07 12:18:13

Computer feels slow and laggy

#2 2010-10-07 16:35:25

Re: Computer feels slow and laggy

#3 2010-10-07 17:00:10

Re: Computer feels slow and laggy

#4 2010-10-07 17:16:24

Re: Computer feels slow and laggy

#5 2010-10-07 17:23:58

Re: Computer feels slow and laggy

#6 2010-10-07 17:35:51

Re: Computer feels slow and laggy

#7 2010-10-07 18:07:52

Re: Computer feels slow and laggy

#8 2010-10-07 19:14:52

Re: Computer feels slow and laggy

#9 2010-10-07 19:23:11

Re: Computer feels slow and laggy

#10 2010-10-08 09:34:00

Re: Computer feels slow and laggy

#11 2010-10-08 15:38:52

Re: Computer feels slow and laggy

#12 2010-10-08 17:19:03

Re: Computer feels slow and laggy

#13 2010-10-09 09:08:33

Re: Computer feels slow and laggy

#14 2010-10-09 09:25:47

Re: Computer feels slow and laggy

#15 2010-10-09 15:19:05

Re: Computer feels slow and laggy

#16 2010-10-09 15:43:46

Re: Computer feels slow and laggy

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