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Hope For Fixing Longstanding Linux I/O Wait Bug

samzenpus posted more than 5 years ago | from the patch-it-up dept.

Bug 180

DaGoodBoy writes "There has been a long standing performance bug in Linux since 2.6.18 that has been responsible for lagging interactivity and poor system performance across all architectures. It has been notoriously difficult to qualify and isolate, but in the last few days someone has finally gotten a repeatable test case! Turns out the problem may not even be disk related, since the test case triggers the bug only by transferring data either between two processes or threads. The test results are very revealing. The developer ran regressions all the way back to version 2.6.15 that demonstrate this bug has more than doubled the time to run the test in 2.6.28. Many, many people working at improving the desktop performance of Linux will be very happy to see this bug die. I know that I, personally, will find a way to send the guy that found this test case his beverage of choice in thanks. Please spread the word and bring some attention to this issue so we can get it fixed!"

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180 comments

funny (0, Troll)

twitter (104583) | more than 5 years ago | (#26461583)

I had not noticed a problem.

Re:funny (1)

the_B0fh (208483) | more than 5 years ago | (#26461659)

That's because you're not transferring data between yourself and another thread.

Re:funny (0)

Anonymous Coward | more than 5 years ago | (#26462007)

Will this make it in to Ubuntu 9.04?

Looks like also affects servers, not just desktops (2, Funny)

trolltalk.com (1108067) | more than 5 years ago | (#26462083)

That's because you're not transferring data between yourself and another thread.

It must also affect servers, because none of the links is transferring data either.

Re:funny (2, Funny)

Waffle Iron (339739) | more than 5 years ago | (#26462533)

That's because you're not transferring data between yourself and another thread.

But he is transferring data between himself and another sockpuppet.

Re:funny (3, Funny)

iluvcapra (782887) | more than 5 years ago | (#26462601)

I trrrrrrrrrrrrrrranssssssssfer data betwwwwwwwwwwwwwwwwwwwwwween threads alllllll the time......

Re:funny (1)

ch0ad (1127549) | more than 5 years ago | (#26464853)

oh is that behaviour due to this bug???? because that was happening on my dad's ubuntu computer

Re:funny (2, Interesting)

Anthony_Cargile (1336739) | more than 5 years ago | (#26461705)

Anyone else notice the article 404ing from the front page? I'd say /. needs to fix some bugs/user errors rather than speak about a Linux IO latency most users don't even notice. Just an observation, and if you can read this, they either fixed it or you doctored up a query string like I did :D.

Re:funny (0)

Anonymous Coward | more than 5 years ago | (#26461733)

Yeah, I saw it too

Re:funny (0)

Anonymous Coward | more than 5 years ago | (#26461947)

I also don't notice any of the horrible problems you keep harping about with Windows. Funny that.

Something else needs to be fixed... (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#26461617)

Please spread the word and bring some attention to this issue so we can get it fixed!

Please someone fix the damn economy for crissakes.

Re:Something else needs to be fixed... (-1, Offtopic)

trolltalk.com (1108067) | more than 5 years ago | (#26462033)

Please spread the word and bring some attention to this issue so we can get it fixed!

Please someone fix the damn economy for crissakes.

That's not going to happen. The current crisis is the result of trying to put off a recession for 8 years, combined with 8 years of criminal ponzi schemes. The current bailout plans will just prolong the time it takes to clear out all the bad debt and bad actors, add to the debt, further devalue the dollar, and delay the inevitable - making it much more painful.

Expectations (Credit Suisse, etc) are that a *minimum* of 1 in 6 US mortgages will default over the next 5 years no matter what, and that the housing market won't hit bottom untl sometime between 2011 and 2016, with another 2 decades before values "return" to their peaks.

Yu can't solve a bad debt crisis with more bad debt, rewarding those responsible for the bad debt, and imposing the burden on those who were prudent. The refusal to bite the bullet over the last 8 years just guarantees that we'll be lucky if we avoid a depression, but that we'll definitely have the worst recesssion this side of 1929-1940.

The chinese have already figured it out. Additionally, they have figured out that it's better to invest their money at home than continue to buy US money long-term, which has already lost between 93 and 98% of its' value in the last 40 years. Long-term US bonds are going to be unsellable internationally a year or two from now, which means print, print, print, and a decade of stagflation, rather than real growth.

Notice how Obama is now saying "create or save jobs" rather than "create jobs." There will be no net creation of jobs over the next 2 years - just people changing from one job to another. This is still better than being unemployed, but it could have been done without the extortion/panic reaction of the bail-outs, which is the largest, most futile Ponzi scheme ever.

Re:Something else needs to be fixed... (0, Troll)

Wonko the Sane (25252) | more than 5 years ago | (#26462065)

For more info see Karl Denninger's blog [market-ticker.org]

Re:Something else needs to be fixed... (-1, Troll)

Anonymous Coward | more than 5 years ago | (#26462543)

if he wants to be taken seriously he needs to stop making his blog look like something a 2 yr old with fontmaker would put together.

Dang!! (5, Funny)

camperdave (969942) | more than 5 years ago | (#26461647)

Dang! I was going for First Post, but my machine was stuck in some weird I/O wait state.

Re:Dang!! (1, Funny)

Aphoxema (1088507) | more than 5 years ago | (#26461763)

Oh, god, I can't read Slashdot commentary and drink fluids at the same time, I never know when something is really going to be funny and I just found out what happens when I stumble across something hilarious while chugging a bottle of water.

Is this bug currently affecting .... (4, Funny)

whoever57 (658626) | more than 5 years ago | (#26461697)

bugzilla.kernel.org?

Re:Is this bug currently affecting .... (3, Funny)

2Bits (167227) | more than 5 years ago | (#26462369)

With the current response time, obviously, yes.

Re:Is this bug currently affecting .... (2, Insightful)

NekoXP (67564) | more than 5 years ago | (#26464277)

Yes, by spreading the word and asking people to go look into fixes we crashed the bug tracker so nobody doing kernel development can file new bugs or new bug fixes for anything else today.

Awesome plan. Really awesome.

Re:Is this bug currently affecting .... (1)

wild_berry (448019) | more than 5 years ago | (#26463627)

Referrals from slashdot are automatically dropped. It's their protection against slashdottings.

Re:Is this bug currently affecting .... (1)

RupW (515653) | more than 5 years ago | (#26464093)

Referrals from slashdot are automatically dropped. It's their protection against slashdottings.

No, that's bugzilla.mozilla.org. The linked bugzilla.kernel.org appears to be down to all traffic.

Re:Is this bug currently affecting .... (1)

tankadin (1175113) | more than 5 years ago | (#26464779)

You just wait till the angry kernel.org guys put slashdot.org link on their page.

KTorrent (2, Interesting)

Anonymous Coward | more than 5 years ago | (#26461711)

I'm not sure if this is related, but has anyone else noticed KTorrent can really bog your system down without showing any excessive resource usage in KSysGuard? For all I know, it may be passing information between one thread and another, and it's disk I/O intensive.

Re:KTorrent (1)

flukus (1094975) | more than 5 years ago | (#26461971)

I've noticed that but I thought it was a bug in KTorrent (since the 4.0 conversion). It seems to only happen at random times and restarting fixes it for me.

Re:KTorrent (2, Informative)

Nuitari The Wiz (1123889) | more than 5 years ago | (#26462047)

There was a bug in ktorrent that cause an infinite loop when udp trackers were present in a torrent file, maybe you check if you have the latest version.

Re:KTorrent (1)

incripshin (580256) | more than 5 years ago | (#26462443)

ktorrent has many confusing bugs in it. I was having trouble running it in OpenBSD-current at some point because the OBSD developers fixed something (probably gcc) that uncovered a bug in ktorrent. A huge memory leak and strange statistics led me to the solution: time was stuck at zero because of a line chock-full of type casts. Still, it has more elusive problems. It would abruptly crash or just go blank, occurring anywhere from 1-24 hours. How do you debug something like that?

Re:KTorrent (0)

Anonymous Coward | more than 5 years ago | (#26462749)

Probably valgrind.

Re:KTorrent (0)

Anonymous Coward | more than 5 years ago | (#26462937)

if you got beagle or some other indexer trying to checksum your files when you have multiple torrents growing all the time this may really cause a lot of IO activity. Even just torrenting to your desktop can cause problems because automatic icon preview creators run each 2 secs to make an icon for your 500 mb movie....

Re:KTorrent (1)

RiotingPacifist (1228016) | more than 5 years ago | (#26463277)

ktorrent isnt great for resources but i find nice & ionice can stop it slowing down desktop preformance. I often wonder why the current active program isn't given a nice boost though so i don't need to remember to tell the background programs (torrent, email, irc, etc)

Re:KTorrent (0)

Anonymous Coward | more than 5 years ago | (#26463845)

I'm using rtorrent and I've never noticed slowdowns when running it, except when it's re-hashing some 4GB of data. On the other hand, I get occasional slowdowns when playing music through pulseaudio and triggering a full-screen redraw (minimizing an application, for example). Worst-case scenario is that it takes two seconds to focus another app. I have always attributed this latency to my processor (sempron 2000+) or the video driver, but it may have been a symptom of this bug.

It will be interesting to see if this fixes anything for me.

Longstanding...Since 2.6.18 (3, Interesting)

akpoff (683177) | more than 5 years ago | (#26461713)

Right. I had to get up in the morning at ten o'clock at night, half an hour before I went to bed, eat a lump of cold poison, work twenty-nine hours a day down mill, and pay mill owner for permission to come to work, and when we got home, our Dad would kill us, and dance about on our graves singing "Hallelujah." --Monty Python: Four Yorkshiremen [davidpbrown.co.uk]

Been waiting all of 2 years and change for your precious bug fix, 'ave you? You almost had my eyes tearing up there I tell ya: 25 Year Old BSD Bug [slashdot.org] .

Re:Longstanding...Since 2.6.18 (1)

Tubal-Cain (1289912) | more than 5 years ago | (#26462841)

--Monty Python: Four Yorkshiremen

25 Year Old BSD Bug

I guess this is the part where is say I don't believe you.

25 years... That bug was older than Linux (or me).

BSD is older than linux and you (0)

Anonymous Coward | more than 5 years ago | (#26464031)

Why was the date of your birth so essential to UNIX OS's that they couldn't have made one until you dropped out your momma's clacker?

Just upgrade (0, Troll)

Toe, The (545098) | more than 5 years ago | (#26461727)

OS not fast enough? Just upgrade your hardware components, preferably to a new, top-of-the-line system.

Oh wait... that's the Windows way of doing things.

Re:Just upgrade (3, Funny)

martinw89 (1229324) | more than 5 years ago | (#26461937)

OS not fast enough? Just upgrade your hardware components, preferably to a new, top-of-the-line system.

Oh wait... that's the Windows way of doing things.

Yeah, exactly, that's why volunteers have been hard at work to find and fix the (published, admitted) bug. Just like Win... Oh, wait.

Re:Just upgrade (0, Flamebait)

pembo13 (770295) | more than 5 years ago | (#26462357)

You have no idea. This seems to be operating procedure in a lot of Windows only shops. I'm not sure if Windows is a factor or just coincidence.

Re:Just upgrade (4, Insightful)

El Lobo (994537) | more than 5 years ago | (#26462609)

Sure, because every Windows developer is a lazy motherfucker that doesn't like his work and plays Solitaire the whole day long, and never ever work fixing things for the love of art. Hard working enthusiastic developers is a Linuzz monopoly.

Re:Just upgrade (2, Interesting)

Erik Hensema (12898) | more than 5 years ago | (#26462911)

It's because people don't want to wait for a bugfix for over 2 years. They need fast systems NOW, and when a performance bug which doesn't get fixed can be solved by buying faster hardware, that's what they do.

Desktop??? (4, Insightful)

corychristison (951993) | more than 5 years ago | (#26461735)

I'm not sure about anybody else here, but I was surprised to see that they mentioned that this will benefit 'Desktop' users.

I think that when it comes to the performance spectrum, Servers would be where this fix is the most needed. Admittedly if you are running a solid server, you should know to use older gen hardware and software that has been proven to be stable. However, some of this 'shiny new' tech coming out is appealing.

How about the Seagate 1500GB drive hang error? To my understanding Windows has been fixed, but the problem still persists in Linux. Could this potentially make a difference? I've been looking to build myself a nice NAS and those 1500GB drives are _cheap_. I can pick one up for about $160. I remember not too long ago that could only get me 80GB.

Re:Desktop??? (1, Interesting)

Anonymous Coward | more than 5 years ago | (#26461781)

I think that when it comes to the performance spectrum, Servers would be where this fix is the most needed.

Nope, read the bug. Throughput remains ok, it's the interactivity that suffers.

This is one of those bugs that no Linux developer will admit to until they reckon they have a fix for it. Then we're supposed to be happy, even though people have been complaining about it for years. Oh well, beggars can't be choosers.

I've been ionice'ing my backups and a few other tasks because of this issue, so it'll be nice to get it fixed.

Re:Desktop??? (2, Interesting)

Compholio (770966) | more than 5 years ago | (#26462003)

I'm actually pretty sure that I've spotted the results of this in "everyday" use. I've noticed that every once in a long while my hard-drive activity kicks up (it's happened when I'm just scrolling on an already-loaded web page and I'm using absolutely zero swap) and literally everything stops responding for a good 5 seconds. My guess would be that the slocate or "tracker" program spawns off on recently added and removed files, but it's not something I've put a lot of effort into figuring out.

Re:Desktop??? (4, Informative)

Anonymous Coward | more than 5 years ago | (#26461853)

I believe the 1.5tb Seagate linux hang has been fixed. We're using a lot of them (100's) where I work on Ubuntu Hardy servers and haven't had hangs.

Re:Desktop??? (1)

jd (1658) | more than 5 years ago | (#26461881)

I remember when that would buy you 60 megabytes! (Hell, I remember when ONE meg drives cost eight times that.)

If you're running a solid server, you know that mechanical devices are (a) slow, and (b) most under strain when doing anything useful, so you tend to avoid using them when at all possible. Servers should do as much as possible via a RAM-based cache -or- use a RAM disk for data that copies to the hard drive only when necessary.

(So long as RAM is battery-backed, even if the machine crashes or the power goes out, you can recover. Your RAM disk needs to be non-volatile just long enough to reboot.)

Better yet, the drive itself would provide such a RAM disk, transparently, so that all you ever saw was a drive that was slow initially but nearly the same speed as RAM for typical usage.

The ideal would be for drives to become truly intelligent devices (ie: have a decent on-board CPU, not HAL-9000 intelligence, which would be bad for data anyway). It would then be possible to have the VFS and whatever underlying FS' you wanted on the drive itself.

Disk-to-disk operations would then bypass the kernel and asynchronous I/O would consume no primary resources. This was fashionable on some systems (most notably drives that used the IEEE 488 bus) in the 70s and was done to some degree with SCSI, but there's really no excuse for not providing such a capability on any modern drive.

Re:Desktop??? (2, Interesting)

adolf (21054) | more than 5 years ago | (#26461935)

Disk-to-disk operations would then bypass the kernel and asynchronous I/O would consume no primary resources. This was fashionable on some systems (most notably drives that used the IEEE 488 bus) in the 70s and was done to some degree with SCSI, but there's really no excuse for not providing such a capability on any modern drive.

I bought that line, hook line and sinker, in the late 90's with a bunch of IBM 9ES ultra-wide SCSI disks and a good controller.

It never was clear to me that, at any time, Linux was actually telling the drives to copy data directly from one disk to any other without the kernel in the middle.

And now that we live in a world of point-to-point serial buses (SATA, SAS) linking disks to seemingly independent controllers: Is it even theoretically possible anymore?

Re:Desktop??? (1)

Nutria (679911) | more than 5 years ago | (#26461983)

Servers should do as much as possible via a RAM-based cache

Right. RAM is C-H-E-A-P

use a RAM disk for data that copies to the hard drive only when necessary.

Wrong. It means you know more about a dynamic system than the kernel.

Re:Desktop??? (3, Funny)

NormalVisual (565491) | more than 5 years ago | (#26462511)

not HAL-9000 intelligence, which would be bad for data anyway

HAL-9K intelligence doesn't pose any problems to the data - it's the *operators* that need to be concerned, especially when giving the system instructions that could potentially conflict with each other.

Re:Desktop??? (1)

k-macjapan (1271084) | more than 5 years ago | (#26462791)

How about the Seagate 1500GB drive hang error? To my understanding Windows has been fixed, but the problem still persists in Linux. Could this potentially make a difference? I've been looking to build myself a nice NAS and those 1500GB drives are _cheap_. I can pick one up for about $160. I remember not too long ago that could only get me 80GB.

You may want to hold off on those Seagate drives. It appears the entire line of 7200.11 are faulty.

http://techreport.com/discussions.x/16232 [techreport.com]

Re:Desktop??? (4, Informative)

cowbutt (21077) | more than 5 years ago | (#26462825)

How about the Seagate 1500GB drive hang error? To my understanding Windows has been fixed, but the problem still persists in Linux.

The ST31500341AS requires a firmware update from Seagate to something newer than revision SD19 (more info [kernel.org] ). In the meantime, if you're using a drive which hasn't been updated to fixed firmware, there's a blacklist in the current development kernel [ozlabs.org] to disable NCQ on affected models as a workaround.

Re:Desktop??? (0)

Anonymous Coward | more than 5 years ago | (#26462873)

they were slow, but it has been fixed with a firmware patch for a while now, check the seagate forums.

Re:Desktop??? (0)

Anonymous Coward | more than 5 years ago | (#26463139)

Did you mean the bug that caused drive to be inaccessible for some time (eg. when you do ls on empty dir you have to wait like 15 seconds to get the result) and after that there was interface reset (dmesg) so that drive would be accessible again?

If that's the case simple toggling sleep modes, power modes, spindown and other things in hdparm.conf did the trick

Re:Desktop??? (0)

Anonymous Coward | more than 5 years ago | (#26463201)

I'm not sure about anybody else here, but I was surprised to see that they mentioned that this will benefit 'Desktop' users.

Hmmm, running a amd64 on gentoo in 64 bit mode, crystal on top of gnome with a usb trackball mouse and keyboard , ive become VERY familiar with these lockups, and Ive seen the weird iowaiting a lot.
It made my desktop unusuable, because I would just be in the middle of retrieving details for a comcall or the like right before the call and *bing*, or id be on a call and someone would want some info and id have to say "hang on a bit, my pc has just locked up"...
ve gone back to using my other 32bit based box out of frustration after reading all the denials of a issue, despite it being mentioned everywhere. I spent a while looking into sata issues thinking it was in there somewhere before having to give up and just go to something useable.

Id say its very important to desktop users...

Re:Desktop??? (0)

Anonymous Coward | more than 5 years ago | (#26463663)

The 1TB and 1.5TB disks from seagate are suffering from firmware problems that brick them up at boot time. Check the seagate forums.

Re:Desktop??? (0)

Anonymous Coward | more than 5 years ago | (#26464729)

This was a firmware problem in the drive itself. See http://www.tow.com/2008/12/12/updating-seagate-15tb-drive-firmware/

Re:Desktop??? (1)

Cryophallion (1129715) | more than 5 years ago | (#26465041)

They are WELL aware of the issue, and there is a firmware patch (there has been for a while now, actually). The issue only seems to present itself in OSX and Linux, which may or may not be due to their common heritage, or jjust lazy quality management. Either way, a quick phone call to them gets you an email with a floppy and cd image for updating the firmware. My myth box has been loving it. The drives are shipping with an different firmware now anyway.

Also, please note that the bug typically happens during slow speed transfers, such as watching videos, so your nas should be ok.

The bug for viewing this (1)

Mordocai (1353301) | more than 5 years ago | (#26461757)

Heh, well i just hit the little link and then hit the link at the top to go back to the main topic... then sent a e-mail to /.

Re:The bug for viewing this (0)

Anonymous Coward | more than 5 years ago | (#26461785)

Linking directly to kernel.org in the story was a tad silly. Poor kernel devs will be lost now.

Re:The bug for viewing this (1)

Mordocai (1353301) | more than 5 years ago | (#26461793)

Heh, well i just hit the little link and then hit the link at the top to go back to the main topic... then sent a e-mail to /.

Yeah, messed up there... meant to put "little comments link"

Killing kernel.org server isn't very nice... (3, Funny)

Anonymous Coward | more than 5 years ago | (#26461771)

I'm sure kernel.org appreciates these links. Now instead of fixing the bug they're putting out fires in the data center...great job slashdot.

Re:Killing kernel.org server isn't very nice... (4, Funny)

statusbar (314703) | more than 5 years ago | (#26461885)


I'm sure kernel.org appreciates these links. Now instead of fixing the bug they're putting out fires in the data center...great job slashdot.

Well, maybe the kernel developers or bugzilla developers could use the practice in making a reliable scalable system out of the systems that they design.

--jeffk++

Re:Killing kernel.org server isn't very nice... (1)

tibman (623933) | more than 5 years ago | (#26464025)

OSS typically doesn't mean lots of $$$ to spend on hardware : /

Windows Port? (4, Funny)

Al Al Cool J (234559) | more than 5 years ago | (#26461811)

If this get resolved is there any chance the fix could get ported to Windows? I just had my Dad's XP laptop completely freeze after I plugged in a bog-basic USB thumbdrive. The desktop sprang to life only after I unplugged it. I wish some of the AC Windows fanboys who were hassling me here last week were around to see it. "Ready for the desktop" my ass.

Re:Windows Port? (0)

Anonymous Coward | more than 5 years ago | (#26461989)

"Not ready for MY desktop" doesn't equal "Not ready for THE desktop".

Re:Windows Port? (0)

Anonymous Coward | more than 5 years ago | (#26463239)

Windows is certainly ready for THE desktop in the sky.

Re:Windows Port? (2, Insightful)

troll8901 (1397145) | more than 5 years ago | (#26462939)

And I'm going to hassle you again.

(Opps, forgot to check the AC option!)

Never mind, carry on ...

(I also have problems with U3 flash drives. I had to use basic flash drives - thus missing out on all the app portability features.)

So THAT's why we don't have Year of the Linux Desktop! It has performance problems ... just like Vista has performance problems!

Re:Windows Port? (1)

hairyfeet (841228) | more than 5 years ago | (#26463039)

Did you plug it in while it was booting? If so, there is your problem. Windows doesn't like you plugging in thumbdrives while booting, especially with certain chipsets. I have found this problem affects the Realtek and Via chipsets more than most. If not, try removing the USB drivers from device manager and hitting refresh, this will allow Windows to reinstall the USB port drivers which can sometimes fix this bug.

Re:Windows Port? (0)

Anonymous Coward | more than 5 years ago | (#26463605)

Not to mention that as Windows will inevitably reboot after the drivers are reinstalled, you'll have an opportunity to find out if it worked.

Gosh those Microsoft people think of everything don't they.

this is bad even for /. (5, Informative)

Harik (4023) | more than 5 years ago | (#26462019)

wow, not just badsummary, utterly worthless summary. Here's the relevant discussion from LKML. Yes, this is all of it.

Peter Zijstra

Andrew Morton
In http://bugzilla.kernel.org/show_bug.cgi?id=12309 [kernel.org] the reporters have
identified what appears to be a sched-related performance regression.
A fairly long-term one - post-2.6.18, perhaps.

Testcase code has been added today. Could someone please take a look
sometime?

There appear to be two different bug reports in there. One about iowait,
and one I'm not quite sure what it is about.

The second thing shows some numbers and a test case, but I fail to see
what the problem is with it.

This somewhat deflates the excitement evident in the OP. I mean, I know what he's talking about, these apparently random 1-2 second FREEZES while working, but if the guys in LKML arn't talking about it it's probably not being really worked on.

Re:this is bad even for /. (2, Interesting)

Anonymous Coward | more than 5 years ago | (#26462429)

The fscking freezes are in HAL. They have been driving me nuts for more than a year. In my case, the solution is to unplug the CDROM drive.

Re:this is bad even for /. (0)

Anonymous Coward | more than 5 years ago | (#26464867)

Less is more, huh?. Right professional OS you have there guv'nor.

Re:this is bad even for /. (2, Funny)

haifastudent (1267488) | more than 5 years ago | (#26462773)

This somewhat deflates the excitement evident in the OP. I mean, I know what he's talking about, these apparently random 1-2 second FREEZES while working, but if the guys in LKML arn't talking about it it's probably not being really worked on.

I know, it looks like someone's pet bug made the cover of /. today. For the record, here is my pet bug: https://launchpad.net/ubuntu/+bug/1 [launchpad.net]

Re:this is bad even for /. (4, Interesting)

bjourne (1034822) | more than 5 years ago | (#26464039)

If you haven't used Linux regularly within the last two years, you probably have not noticed that the system has gotten significantly slower with more recent releases. The probable symptom was discussed here [slashdot.org] . Many Ubuntu users, including me, have noticed that the latency of desktop operations got significantly larger around the time Gutsy was released, which coincides with the Completely Fair Scheduler and kernel upgrade from 2.6.18.

Since it is most likely a latency issue, the problem is extremely hard to diagnose. Alt-tabbing between programs seem a little slower, keyboard input might lag somewhat. You can't measure desktop latency easily.

Re:this is bad even for /. (2, Interesting)

Anonymous Coward | more than 5 years ago | (#26464171)

It's very easy to trigger, just unrar an iso from a torrent. Regardless of CPU cores, copious amounts of RAM, and no other real system activity, your desktop experience will grind to a miserable halt until the archive process has completed. renicing makes very little difference. Linux has had this problem for years, certainly more than two. Memory suggests it came along with SATA.

bugzillas been /.'d (0)

Anonymous Coward | more than 5 years ago | (#26462527)

Linky taking too long to respond... oh wells :-)

bugzilla.kernel.org is slashdotted! (0)

Anonymous Coward | more than 5 years ago | (#26462613)

Give us a way to get your test program you've attached to the bug...

Karlan Mitchell (0)

Anonymous Coward | more than 5 years ago | (#26462889)

Hmm, I use 2.6.28 and on a duo core it kinda? and eventually freezes up whenever I try to burn a audio cd only, I've tried different cdrecord, no avail, lower kernel, not avail........ Showed up recently after kernel upgrade

Re:Karlan Mitchell (1)

syberdave (658106) | more than 5 years ago | (#26463817)

2.6.28 introduced an option for Preemption.

(Processor type and features --> Preemption model.)

Pick voluntary kernel preemption.

"beverage of choice" ??? (-1, Troll)

Anonymous Coward | more than 5 years ago | (#26462897)

This sort of sums up the Free Software community -
that any amount of work is worth no more than a few Euro.
Very sad.
Deeply insulting.
Clearly the person that wrote this has no kids to send to college or retirement to worry about.

Re:"beverage of choice" ??? (1)

Alain Williams (2972) | more than 5 years ago | (#26463157)

Surely the sending of a small gift is a token of appreciation akin to a pat on the back. If we had paid for the s/ware, would someone not directly connected with the bug finder even do that ?

From your tone: I assume that you will be sending this guy something of great value ?

Why do you not have the courage to say your name when you post ?

Re:"beverage of choice" ??? (0)

Anonymous Coward | more than 5 years ago | (#26463441)

If we had paid for the software, then the bug finder would be receiving 100k a year, and not just "appreciation"!!

Paul Sheer

Re:"beverage of choice" ??? (1)

mabinogi (74033) | more than 5 years ago | (#26463851)

but he would not be receiving 100k a year from individuals that were happy with his work.

Quite a few of the core kernel developers actually _are_ paid to work on the kernel these days.
Whether or not the end users pay for it has nothing to do with whether or not the developers get paid.

In addition, if this test case has come from the community, then it would _never have happened_ if the kernel was not an open source project.

I second this (5, Interesting)

waslap (1453217) | more than 5 years ago | (#26462933)

I am overjoyed that my suspicions have finally been vindicated. I've been working 10+hours a day on linux for the last 13years and you tend to get in tune with your environment (i can still today recite my DOS bootup tune on my XT even though I haven't worked on it for 20 years:-) and some time ago after installing a new flavour of linux I immediately started complaining to fellow workers that something has gone wrong in the kernel but it was not annoying enough to really do something about it; you start living with it. It manifests sometimes when I compile - my system simply locks up for 20-30 seconds which is something I never experienced before. I'd say it happens once out of every 50 compiles of the same program with gcc. During such occurrences, I can't access anything on my desktop which annoyes me cause I typically switch to another kterm session to prepare to run the build whilst compiling (to keep up the productivity and all that). I have also seen strange ratios of i/o to cpu wait in 'top' nowadays but can probably ascribe that to CPU's that just became ridiculously fast and the way top calculates its scores. Nevertheless, I've mumbled over and lambasted i/o wait in Linux ever since a very specific time in the past and even though I haven't noted the exact date, I'm sure its related to this. Anyway, I found this intrigueing enough to create a slashdot account after years to share my joy that the bugs days are hopefully numbered now.

I hope they are going to fix GCC, too (0)

Anonymous Coward | more than 5 years ago | (#26464561)

Yes, that's right. I've also noticed that kernel 2.2 on an older PC is still much faster than 2.6 kernel on a new one. Especially when compiling.

Another source of trouble is the increasing bloatedness in GCC. 2.95.3 is still a neat and fast compiler, while GCC 3 and GCC 4 are so slow and big. And then this constant fiddling with the C++ standard. You can't even write a C++ program these days and be sure that it will compile in 3-4 years. That sucks.

Linux mint freeze (0)

Anonymous Coward | more than 5 years ago | (#26462965)

Could this be the mystery freeze in Linux Mint that forces a hard reset??

Problem is Real (5, Informative)

Anonymous Coward | more than 5 years ago | (#26463001)

For what it is worth, the problem is real.

We have experienced massive negative effects with our MySQL server; downgrading to early linux kernel solves the problem. This has been very difficult to debug as we never guessed that the OS would be a factor... we figured it had to be something we were doing. Only by chance did we try another distro / kernel only to find that everything starts working fine when you downgrade.

Re:Problem is Real (2, Interesting)

Bert64 (520050) | more than 5 years ago | (#26463165)

What version do you need to downgrade to? And does downgrading open you up to any security flaws or incompatibility?

Re:Problem is Real (4, Insightful)

Harik (4023) | more than 5 years ago | (#26463251)

If you can reproduce it, do a git-bisect. You'll find the change that caused it pretty quickly.

Re:Problem is Real (1, Interesting)

Anonymous Coward | more than 5 years ago | (#26464609)

Different AC here.

I've already started doing a git bisect on some of the versions. My findings are at home (i'm at work), but there was a difference whereby a newer kernel version had worse performance that an older version.

What tends to happen is that intra-disk and inter-disk transfers are very fast (DMA is on), at the expense of X11 responsiveness. GUI operations (minimise windows, mouse clicks) start to lag. Not sure if this is the same problem as in the article.

I really could do with spending a good few days investigating and bisecting. I hope this is fixed soon.

poor old firefox is knocked off it's shelf (1, Funny)

Anonymous Coward | more than 5 years ago | (#26463241)

and here I was thinking that those pauses were because I had firefox open with >5 tabs for >1 hour.

This is what happens... (2)

Builder (103701) | more than 5 years ago | (#26463721)

...when you insist on doing development in the 'stable' kernel tree and expect vendors to stablise it.

Genius!

Alcohol (ab)use (0)

Anonymous Coward | more than 5 years ago | (#26464431)

I know that I, personally, will find a way to send the guy that found this test case his beverage of choice in thanks. Please spread the word and bring some attention to this issue so we can get it fixed!

Is this your plan? [xkcd.com]

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