System slowdown during large file I/O

I've been having this problem for a little while now and it has finally annoyed me to the point where I have to ask for some help to fix it. For some reason, when I do large file writes or reads the I/O itself seems to take a lot longer than it used to on other Linuxes i've tried and the system becomes a bit unresponsive. This happens whether I am writing to my serial ATA drive, reading from it, or writing to my USB backup drive. Additionally, I think this problem is also manifesting itself when I try to play video files. The HD video files that I have will sometimes lag for up to 10 or 15 seconds if I seek forward or backwards in the file in mplayer. For smaller videos the lag will range anywhere from as low as instantaneous (normal) up to 3 or 4 seconds before recovering. Also, I noticed that when I copy large (where "large" means > 100 MB or so) files and I am listening to music, the music will cut out/pause for a second or two at a time every few seconds until the file is transfered. Finally, the last bit of evidence that I noticed is when I dragged/dropped a large file from one place onto my desktop and the GNOME file transfer dialogue that popped up (which shows speed) said I was only copying ~3 or 4 MB / sec. As far as I remember, the write speeds should be a bit more than 10x that much. I'd say perhaps their measurement/estimate is wrong, but the file transfers seem to take a lot longer than they should, which lends credance to their estimate.

I'd SERIOUSLY appreciate any help you guys can provide. I know it isn't my hardware because it works ok under windows/other linuxes, and in all likelihood I probably configured something wrong because I am still new to gentoo. Thanks in advance!

-Zorak

Yeah, actually Linux_0 was kind enough to get on aim and help me out with similar suggestions that you have posted here. So I installed hdparm and smartmontools and a couple of other things and when i ran hdparm -t /dev/[sh]d[acd] i got results back that my IDE drive was working normally (~40MB/sec) and that my two SATA drives were reading at ~4MB/sec. So, i figured it was probably a software problem (bad or misconfigured software) since the drives work fine under windows and ubuntu, so I booted up with an Ubuntu LiveCD. After installing hdparm under the live environment I got much more normal numbers for the IDE and 2 SATA drives (~40 ~65 ~65), so I verified that my drives should work normally under Linux (or at least ubuntu). My next step will be to go and boot up with the gentoo liveCD and see whether or not the drives work properly under that live environment. If they do, I will attempt to figure out which software they are loading for SATA and see if I can compile in support for it in my kernel. As a last resort, I will move to genkernel like Linux_0 suggests, but at this moment I feel like the solution should be close enough for me to grasp, making movement to genkernel unnecessary.

I haven't had time to do any troubleshooting since Monday evening when Linux_0 helped me out, but as soon as I get the chance i will continue and I will post the results here.

Thanks guys!

-Zorak

[Klink] veeeeery interesting[/klink]

You'll have to let us know the results of the other livecd

Hmmmm, don' think knowing my drivers would help you, but I would be interested to see what modules are being loaded by the ubuntu and gentoo livecd's to compare and contrast. But if you want to know anyway, I have the nvidia SATA support built in for my standard disks

(option CONFIG_SATA_NV, location

Device Drivers->
__Serial ATA(prod) and Parallel ATA (experimental) drivers->
____<*>NVIDIA SATA Support
)

and 3ware 9xxx SATA-RAID support built in for my 3ware escalade 9500s

(option CONFIG_SCSI_3W_9XXX location

Device Drivers->
__SCSI device support->
____SCSI low-level drivers->
______<*>3ware 9xxx SATA-RAID support
)

I'd say your best bet now is to compare/contrast the modules that are being loaded by the two livecds since there's a disparity there

First of all I would like to say this:


Chaac ~ # hdparm -tT /dev/sda; hdparm -tT /dev/sdb; hdparm -tT /dev/sdc

/dev/sda:
Timing cached reads: 7958 MB in 2.00 seconds = 3982.17 MB/sec
Timing buffered disk reads: 184 MB in 3.00 seconds = 61.25 MB/sec

/dev/sdb:
Timing cached reads: 7204 MB in 2.00 seconds = 3604.26 MB/sec
Timing buffered disk reads: 178 MB in 3.02 seconds = 58.88 MB/sec

/dev/sdc:
Timing cached reads: 7514 MB in 2.00 seconds = 3760.63 MB/sec
Timing buffered disk reads: 128 MB in 3.00 seconds = 42.65 MB/sec


I think the results speak for themselves

I want to thank you guys for all your help and especially Linux_0 for helping me confirm that this was indeed a misconfigured driver by showing me the tools necessary to diagnose the problem and for actually coming on AIM just to help me out. I also want to thank the wonderful people at #gentoo who helped me figure out that in particular it was the old ATA driver in the ATA/... section of the menuconfig that was conflicting with my SATA drivers.

The solution ended up being that I just turned off the old drivers (I had both turned on) and then turn on ACHI mode in my BIOS for my SATA controller and then recompile the kernel and change grub and fstab to reflect the new partition names I admit that to a linux newbie this would all be incomprehensible, but if you know what each thing does, it makes sense I guess that shows that I have really learned quite a bit since i started messing with FC2 way back in '05.

Anyways, THANK YOU GUYS SO MUCH!

-Zorak