* Article in Phoronix about loss of performance in 2.6.35 release candidates
@ 2010-05-31 23:19 Alex Buell
2010-05-31 23:39 ` Robert Hancock
2010-06-01 4:10 ` tytso
0 siblings, 2 replies; 14+ messages in thread
From: Alex Buell @ 2010-05-31 23:19 UTC (permalink / raw)
To: Mailing Lists - Kernel Developers
http://www.phoronix.com/vr.php?view=14976
Question: Why?
--
http://www.munted.org.uk
One very high maintenance cat living here.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-05-31 23:19 Article in Phoronix about loss of performance in 2.6.35 release candidates Alex Buell
@ 2010-05-31 23:39 ` Robert Hancock
2010-06-01 0:46 ` Alex Buell
2010-06-01 3:15 ` Bill Davidsen
2010-06-01 4:10 ` tytso
1 sibling, 2 replies; 14+ messages in thread
From: Robert Hancock @ 2010-05-31 23:39 UTC (permalink / raw)
To: alex.buell; +Cc: Mailing Lists - Kernel Developers
On 05/31/2010 05:19 PM, Alex Buell wrote:
> http://www.phoronix.com/vr.php?view=14976
>
> Question: Why?
Good question.. I guess it would too much to ask of them to try to
figure out what area the problem lies in (even to the point of figuring
out if it's a CPU or IO-bound problem), or try to bisect, or at least
report it to LKML before going to the trouble of creating 5 pages of
graphs.. Given the 20x slowdown in some of the benchmarks you'd think it
wouldn't be too hard to narrow down.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-05-31 23:39 ` Robert Hancock
@ 2010-06-01 0:46 ` Alex Buell
2010-06-01 0:52 ` Dave Airlie
2010-06-01 3:15 ` Bill Davidsen
1 sibling, 1 reply; 14+ messages in thread
From: Alex Buell @ 2010-06-01 0:46 UTC (permalink / raw)
To: Mailing Lists - Kernel Developers
On Mon, 2010-05-31 at 17:39 -0600, Robert Hancock wrote:
> On 05/31/2010 05:19 PM, Alex Buell wrote:
> > http://www.phoronix.com/vr.php?view=14976
> >
> > Question: Why?
>
> Good question.. I guess it would too much to ask of them to try to
> figure out what area the problem lies in (even to the point of figuring
> out if it's a CPU or IO-bound problem), or try to bisect, or at least
> report it to LKML before going to the trouble of creating 5 pages of
> graphs.. Given the 20x slowdown in some of the benchmarks you'd think it
> wouldn't be too hard to narrow down.
What I really don't get is why they didn't talk to people on
linux-kernel before posting those claims on phoronix. :S
--
http://www.munted.org.uk
One very high maintenance cat living here.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 0:46 ` Alex Buell
@ 2010-06-01 0:52 ` Dave Airlie
0 siblings, 0 replies; 14+ messages in thread
From: Dave Airlie @ 2010-06-01 0:52 UTC (permalink / raw)
To: alex.buell; +Cc: Mailing Lists - Kernel Developers
On Tue, Jun 1, 2010 at 10:46 AM, Alex Buell <alex.buell@munted.org.uk> wrote:
> On Mon, 2010-05-31 at 17:39 -0600, Robert Hancock wrote:
>> On 05/31/2010 05:19 PM, Alex Buell wrote:
>> > http://www.phoronix.com/vr.php?view=14976
>> >
>> > Question: Why?
>>
>> Good question.. I guess it would too much to ask of them to try to
>> figure out what area the problem lies in (even to the point of figuring
>> out if it's a CPU or IO-bound problem), or try to bisect, or at least
>> report it to LKML before going to the trouble of creating 5 pages of
>> graphs.. Given the 20x slowdown in some of the benchmarks you'd think it
>> wouldn't be too hard to narrow down.
>
> What I really don't get is why they didn't talk to people on
> linux-kernel before posting those claims on phoronix. :S
Well thats kinda obvious, its "journalism" in the days of google
adwords. They make revenue by making people click on their website,
they don't make money being useful or interacting with others.
Phoronix in all the years I've been dealing with them as the only
place doing any reporting on graphics, have never once confirmed a
source, asked for information directly or anything you'd expect from
real journalists, again because that doesn't drive page hits, whereas
sensationalist useless headlines are the main point of the site.
Dave.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-05-31 23:39 ` Robert Hancock
2010-06-01 0:46 ` Alex Buell
@ 2010-06-01 3:15 ` Bill Davidsen
2010-06-01 3:22 ` Robert Hancock
1 sibling, 1 reply; 14+ messages in thread
From: Bill Davidsen @ 2010-06-01 3:15 UTC (permalink / raw)
To: Robert Hancock; +Cc: alex.buell, Mailing Lists - Kernel Developers, Dave Airlie
Robert Hancock wrote:
> On 05/31/2010 05:19 PM, Alex Buell wrote:
>> http://www.phoronix.com/vr.php?view=14976
>>
>> Question: Why?
>
> Good question.. I guess it would too much to ask of them to try to
> figure out what area the problem lies in (even to the point of figuring
> out if it's a CPU or IO-bound problem), or try to bisect, or at least
> report it to LKML before going to the trouble of creating 5 pages of
> graphs.. Given the 20x slowdown in some of the benchmarks you'd think it
> wouldn't be too hard to narrow down.
That's true, but 20x should be too hard for people to detect when they do QA
after creating a patch, before sending it to LKML in the first place, either. If
such a regression made it to an -rc1 then it really is kind of a big deal. Of
course Phoronics running the tests on netbook processors is probably a good
thing, I doubt many developers and testers are compiling kernels on a rig like
that, or doing much of anything else demanding.
I guess I would expect people to react with dismay to the fact that such a
problem made it undetected to rc stage, but perhaps I have too much respect for
developers. This looks more like "how dare they not keep it quiet and just tell
us" indignation. In the end I doubt it makes a lot of difference, if someone
posted to LKML and Slashdot picked it up, be sure it would have hit the media
anyway.
Should any media keep a defect quiet when they make their living informing the
readers? I see a lot of glee among Linux users every few days when a new Windows
bug becomes public. Phoronics tested and reported, why is that less honorable
than Tom's Hardware telling us a new CPU sucks?
--
Bill Davidsen <davidsen@tmr.com>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 3:15 ` Bill Davidsen
@ 2010-06-01 3:22 ` Robert Hancock
2010-06-01 5:38 ` Mike Galbraith
0 siblings, 1 reply; 14+ messages in thread
From: Robert Hancock @ 2010-06-01 3:22 UTC (permalink / raw)
To: Bill Davidsen; +Cc: alex.buell, Mailing Lists - Kernel Developers, Dave Airlie
On Mon, May 31, 2010 at 9:15 PM, Bill Davidsen <davidsen@tmr.com> wrote:
> Robert Hancock wrote:
>>
>> On 05/31/2010 05:19 PM, Alex Buell wrote:
>>>
>>> http://www.phoronix.com/vr.php?view=14976
>>>
>>> Question: Why?
>>
>> Good question.. I guess it would too much to ask of them to try to figure
>> out what area the problem lies in (even to the point of figuring out if it's
>> a CPU or IO-bound problem), or try to bisect, or at least report it to LKML
>> before going to the trouble of creating 5 pages of graphs.. Given the 20x
>> slowdown in some of the benchmarks you'd think it wouldn't be too hard to
>> narrow down.
>
> That's true, but 20x should be too hard for people to detect when they do QA
> after creating a patch, before sending it to LKML in the first place,
> either. If such a regression made it to an -rc1 then it really is kind of a
> big deal. Of course Phoronics running the tests on netbook processors is
> probably a good thing, I doubt many developers and testers are compiling
> kernels on a rig like that, or doing much of anything else demanding.
>
> I guess I would expect people to react with dismay to the fact that such a
> problem made it undetected to rc stage, but perhaps I have too much respect
> for developers. This looks more like "how dare they not keep it quiet and
> just tell us" indignation. In the end I doubt it makes a lot of difference,
> if someone posted to LKML and Slashdot picked it up, be sure it would have
> hit the media anyway.
>
> Should any media keep a defect quiet when they make their living informing
> the readers? I see a lot of glee among Linux users every few days when a new
> Windows bug becomes public. Phoronics tested and reported, why is that less
> honorable than Tom's Hardware telling us a new CPU sucks?
Of course they shouldn't keep it quiet. The problem is they went and
wrote an article that was basically "OMG HUGE PERFORMANCE LOSS!!1!!"
without reporting the problem to people that can actually do something
about it, and also didn't provide any very useful details like dmesg,
config, etc. that might let someone figure out what's going on.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-05-31 23:19 Article in Phoronix about loss of performance in 2.6.35 release candidates Alex Buell
2010-05-31 23:39 ` Robert Hancock
@ 2010-06-01 4:10 ` tytso
2010-06-01 5:00 ` Pekka Enberg
2010-06-01 6:35 ` Ingo Molnar
1 sibling, 2 replies; 14+ messages in thread
From: tytso @ 2010-06-01 4:10 UTC (permalink / raw)
To: Alex Buell; +Cc: Mailing Lists - Kernel Developers, Eric Paris
On Tue, Jun 01, 2010 at 12:19:29AM +0100, Alex Buell wrote:
> http://www.phoronix.com/vr.php?view=14976
>
> Question: Why?
One of the theories that has been advanced is that it's simply this
problem:
http://lkml.org/lkml/2010/5/22/154
If so, it points out how idiotic Phoronix is about not being able to
notice udev pegging the CPU at 100% being someone bad for its
benchmark runs. :-)
OTOH, this bug has been known for over a week, and it is sort sad that
we haven't reverted this patch. It looks like the conversation has
died, but without a fix?
- Ted
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 4:10 ` tytso
@ 2010-06-01 5:00 ` Pekka Enberg
2010-06-01 6:17 ` Ingo Molnar
2010-06-01 12:44 ` Chris Mason
2010-06-01 6:35 ` Ingo Molnar
1 sibling, 2 replies; 14+ messages in thread
From: Pekka Enberg @ 2010-06-01 5:00 UTC (permalink / raw)
To: tytso, Alex Buell, Mailing Lists - Kernel Developers, Eric Paris,
Linus Torvalds, Arjan van de Ven, Ingo Molnar
On Tue, Jun 1, 2010 at 7:10 AM, <tytso@mit.edu> wrote:
> On Tue, Jun 01, 2010 at 12:19:29AM +0100, Alex Buell wrote:
>> http://www.phoronix.com/vr.php?view=14976
>>
>> Question: Why?
>
> One of the theories that has been advanced is that it's simply this
> problem:
>
> http://lkml.org/lkml/2010/5/22/154
>
> If so, it points out how idiotic Phoronix is about not being able to
> notice udev pegging the CPU at 100% being someone bad for its
> benchmark runs. :-)
>
> OTOH, this bug has been known for over a week, and it is sort sad that
> we haven't reverted this patch. It looks like the conversation has
> died, but without a fix?
It's fixed by 1eb2cbb6d5efe129 so the problem doesn't exist for 2.6.35-r1.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 3:22 ` Robert Hancock
@ 2010-06-01 5:38 ` Mike Galbraith
0 siblings, 0 replies; 14+ messages in thread
From: Mike Galbraith @ 2010-06-01 5:38 UTC (permalink / raw)
To: Robert Hancock
Cc: Bill Davidsen, alex.buell, Mailing Lists - Kernel Developers,
Dave Airlie
On Mon, 2010-05-31 at 21:22 -0600, Robert Hancock wrote:
> On Mon, May 31, 2010 at 9:15 PM, Bill Davidsen <davidsen@tmr.com> wrote:
> > Robert Hancock wrote:
> >>
> >> On 05/31/2010 05:19 PM, Alex Buell wrote:
> >>>
> >>> http://www.phoronix.com/vr.php?view=14976
> >>>
> >>> Question: Why?
> >>
> >> Good question.. I guess it would too much to ask of them to try to figure
> >> out what area the problem lies in (even to the point of figuring out if it's
> >> a CPU or IO-bound problem), or try to bisect, or at least report it to LKML
> >> before going to the trouble of creating 5 pages of graphs.. Given the 20x
> >> slowdown in some of the benchmarks you'd think it wouldn't be too hard to
> >> narrow down.
> >
> > That's true, but 20x should be too hard for people to detect when they do QA
> > after creating a patch, before sending it to LKML in the first place,
> > either. If such a regression made it to an -rc1 then it really is kind of a
> > big deal. Of course Phoronics running the tests on netbook processors is
> > probably a good thing, I doubt many developers and testers are compiling
> > kernels on a rig like that, or doing much of anything else demanding.
> >
> > I guess I would expect people to react with dismay to the fact that such a
> > problem made it undetected to rc stage, but perhaps I have too much respect
> > for developers. This looks more like "how dare they not keep it quiet and
> > just tell us" indignation. In the end I doubt it makes a lot of difference,
> > if someone posted to LKML and Slashdot picked it up, be sure it would have
> > hit the media anyway.
> >
> > Should any media keep a defect quiet when they make their living informing
> > the readers? I see a lot of glee among Linux users every few days when a new
> > Windows bug becomes public. Phoronics tested and reported, why is that less
> > honorable than Tom's Hardware telling us a new CPU sucks?
>
> Of course they shouldn't keep it quiet. The problem is they went and
> wrote an article that was basically "OMG HUGE PERFORMANCE LOSS!!1!!"
> without reporting the problem to people that can actually do something
> about it, and also didn't provide any very useful details like dmesg,
> config, etc. that might let someone figure out what's going on.
Shrug. If eggshells land in our omelet, they can make a buck telling
people about it. Who cares? If tasty bacon bits land, they'll make a
buck on that event. Either way, we get some test coverage.
-Mike
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 5:00 ` Pekka Enberg
@ 2010-06-01 6:17 ` Ingo Molnar
2010-06-01 6:25 ` Ingo Molnar
2010-06-01 6:53 ` Ingo Molnar
2010-06-01 12:44 ` Chris Mason
1 sibling, 2 replies; 14+ messages in thread
From: Ingo Molnar @ 2010-06-01 6:17 UTC (permalink / raw)
To: Pekka Enberg, Alexander Viro
Cc: tytso, Alex Buell, Mailing Lists - Kernel Developers, Eric Paris,
Linus Torvalds, Arjan van de Ven
* Pekka Enberg <penberg@cs.helsinki.fi> wrote:
> On Tue, Jun 1, 2010 at 7:10 AM, <tytso@mit.edu> wrote:
> > On Tue, Jun 01, 2010 at 12:19:29AM +0100, Alex Buell wrote:
> >> http://www.phoronix.com/vr.php?view=14976
> >>
> >> Question: Why?
> >
> > One of the theories that has been advanced is that it's simply this
> > problem:
> >
> > ? ? ? ?http://lkml.org/lkml/2010/5/22/154
> >
> > If so, it points out how idiotic Phoronix is about not being able to
> > notice udev pegging the CPU at 100% being someone bad for its
> > benchmark runs. ?:-)
> >
> > OTOH, this bug has been known for over a week, and it is sort sad that
> > we haven't reverted this patch. ?It looks like the conversation has
> > died, but without a fix?
>
> It's fixed by 1eb2cbb6d5efe129 so the problem doesn't exist for 2.6.35-r1.
Btw., the changelog in 1eb2cbb6d5efe129:
| From 1eb2cbb6d5efe129cd006691267ce513c0aa59da Mon Sep 17 00:00:00 2001
| From: Al Viro <viro@zeniv.linux.org.uk>
| Date: Thu, 27 May 2010 11:11:06 -0400
| Subject: [PATCH] Revert "anon_inode: set S_IFREG on the anon_inode"
|
| This reverts commit a7cf4145bb86aaf85d4d4d29a69b50b688e2e49d.
| ---
| fs/anon_inodes.c | 2 +-
| 1 files changed, 1 insertions(+), 1 deletions(-)
Is lacking pretty much all essential pieces of information which are required
for reverts:
- it has no description about who reported the bug.
- it has no description about what the problem was and what the effects were.
People have little chance to link up the 'udev is spinning' bug to
this fix.
- it has no link back to '3836a03: anon_inodes: mark the anon inode private'
which introduced it and hence it has no -stable tag either.
- has no signoff line
Ingo
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 6:17 ` Ingo Molnar
@ 2010-06-01 6:25 ` Ingo Molnar
2010-06-01 6:53 ` Ingo Molnar
1 sibling, 0 replies; 14+ messages in thread
From: Ingo Molnar @ 2010-06-01 6:25 UTC (permalink / raw)
To: Pekka Enberg, Alexander Viro
Cc: tytso, Alex Buell, Mailing Lists - Kernel Developers, Eric Paris,
Linus Torvalds, Arjan van de Ven
* Ingo Molnar <mingo@elte.hu> wrote:
> Is lacking pretty much all essential pieces of information which are
> required for reverts:
>
> - it has no description about who reported the bug.
In fact it was _bisected_ by Eric Paris, so a Bisected-by tag is a must.
Eric is a nice guy and i'm sure wont complain about this, but i can tell it
with a 100% certainty that to most testers and developers bisecting bugs is a
tiresome and error-prone process that involves quite a bit of work.
Bisecting a bug is often more work to do than the work which went into the
original commit and the revert, combined.
So if we want more people to test our commits then the least we can do is to
credit testers by making proper use of the Reported-by and Bisected-by tags.
Ingo
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 4:10 ` tytso
2010-06-01 5:00 ` Pekka Enberg
@ 2010-06-01 6:35 ` Ingo Molnar
1 sibling, 0 replies; 14+ messages in thread
From: Ingo Molnar @ 2010-06-01 6:35 UTC (permalink / raw)
To: tytso, Alex Buell, Mailing Lists - Kernel Developers, Eric Paris
* tytso@mit.edu <tytso@mit.edu> wrote:
> On Tue, Jun 01, 2010 at 12:19:29AM +0100, Alex Buell wrote:
> > http://www.phoronix.com/vr.php?view=14976
> >
> > Question: Why?
>
> One of the theories that has been advanced is that it's simply this problem:
>
> http://lkml.org/lkml/2010/5/22/154
>
> If so, it points out how idiotic Phoronix is about not being able to notice
> udev pegging the CPU at 100% being someone bad for its benchmark runs. :-)
They might be 'minimally helpful' and they might want to maximize clicks, but
IMO that doesnt equate to 'idiotic', at all. The slowdown was real and they
have no obligation to figure out what caused it.
Think what an ordinary tester would do: install -rc1, see a slowdown, skip
back to v2.6.34. Reporting the 'macro performance' metrics is useful.
As Linux gets more and more mainstream we should get used to
selfish/hostile/unhelpful journalism, just like we had to get used to
selfish/hostile/unhelpful users, developers, etc. This isnt directed at Linux,
this is simply an unavoidable side effect of becoming more mainstream. And
there will be more of this, hopefully ;-)
Thanks,
Ingo
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 6:17 ` Ingo Molnar
2010-06-01 6:25 ` Ingo Molnar
@ 2010-06-01 6:53 ` Ingo Molnar
1 sibling, 0 replies; 14+ messages in thread
From: Ingo Molnar @ 2010-06-01 6:53 UTC (permalink / raw)
To: Pekka Enberg, Alexander Viro
Cc: tytso, Alex Buell, Mailing Lists - Kernel Developers, Eric Paris,
Linus Torvalds, Arjan van de Ven
* Ingo Molnar <mingo@elte.hu> wrote:
> - it has no link back to '3836a03: anon_inodes: mark the anon inode private'
> which introduced it and hence it has no -stable tag either.
Ah, it got introduced by a7cf4145bb86 so no -stable relevancy.
Ingo
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Article in Phoronix about loss of performance in 2.6.35 release candidates
2010-06-01 5:00 ` Pekka Enberg
2010-06-01 6:17 ` Ingo Molnar
@ 2010-06-01 12:44 ` Chris Mason
1 sibling, 0 replies; 14+ messages in thread
From: Chris Mason @ 2010-06-01 12:44 UTC (permalink / raw)
To: Pekka Enberg
Cc: tytso, Alex Buell, Mailing Lists - Kernel Developers, Eric Paris,
Linus Torvalds, Arjan van de Ven, Ingo Molnar
On Tue, Jun 01, 2010 at 08:00:39AM +0300, Pekka Enberg wrote:
> On Tue, Jun 1, 2010 at 7:10 AM, <tytso@mit.edu> wrote:
> > On Tue, Jun 01, 2010 at 12:19:29AM +0100, Alex Buell wrote:
> >> http://www.phoronix.com/vr.php?view=14976
> >>
> >> Question: Why?
> >
> > One of the theories that has been advanced is that it's simply this
> > problem:
> >
> > http://lkml.org/lkml/2010/5/22/154
> >
> > If so, it points out how idiotic Phoronix is about not being able to
> > notice udev pegging the CPU at 100% being someone bad for its
> > benchmark runs. :-)
> >
> > OTOH, this bug has been known for over a week, and it is sort sad that
> > we haven't reverted this patch. It looks like the conversation has
> > died, but without a fix?
>
> It's fixed by 1eb2cbb6d5efe129 so the problem doesn't exist for 2.6.35-r1.
When I first read this email, I thought it meant the test was done
on rc1, but reading the article:
To cut to the chase, between the 22nd and 24th of May there
looks to be at least one commit (though perhaps multiple based
upon the different data) within the Linus Torvalds 2.6 Git tree
that are negatively affecting many different server/desktop
benchmarks. We waited nearly a week to see if these regressions
would be organically caught and addressed, but they have not
been at least of the Linux 2.6 Git state as of 2010-05-26.
I'll give the udev fix a try w/the btrfs tests.
-chris
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2010-06-01 12:52 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-05-31 23:19 Article in Phoronix about loss of performance in 2.6.35 release candidates Alex Buell
2010-05-31 23:39 ` Robert Hancock
2010-06-01 0:46 ` Alex Buell
2010-06-01 0:52 ` Dave Airlie
2010-06-01 3:15 ` Bill Davidsen
2010-06-01 3:22 ` Robert Hancock
2010-06-01 5:38 ` Mike Galbraith
2010-06-01 4:10 ` tytso
2010-06-01 5:00 ` Pekka Enberg
2010-06-01 6:17 ` Ingo Molnar
2010-06-01 6:25 ` Ingo Molnar
2010-06-01 6:53 ` Ingo Molnar
2010-06-01 12:44 ` Chris Mason
2010-06-01 6:35 ` Ingo Molnar
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