![]() | ||||||||||
Messages in this thread |
On Fri, Mar 14, 2008 at 08:50:19AM +0800, Zhang, Yanmin wrote: > On Thu, 2008-03-13 at 10:12 -0700, Greg KH wrote:> > On Thu, Mar 13, 2008 at 09:19:21AM -0700, Randy Dunlap wrote: > > > On Thu, 13 Mar 2008 08:14:13 -0700 Greg KH wrote:> > > > > > > On Thu, Mar 13, 2008 at 03:46:57PM +0800, Zhang, Yanmin wrote: > > > > > Comparing with 2.6.24, on my 16-core tigerton, hackbench process mode has about > > > > > 40% regression with 2.6.25-rc1, and more than 20% regression with kernel > > > > > 2.6.25-rc4, because rc4 includes the reverting patch of scheduler load balance. > > > > > > > > > > Command to start it.> > > > > #hackbench 100 process 2000> > > > > I ran it for 3 times and sum the values.> > > > > > > > > > I tried to investiagte it by bisect.> > > > > Kernel up to tag 0f4dafc0563c6c49e17fe14b3f5f356e4c4b8806 has the 20% regression. > > > > > Kernel up to tag 6e90aa972dda8ef86155eefcdbdc8d34165b9f39 hasn't regression. > > > > > > > > > > Any bisect between above 2 tags cause kernel hang. I tried to checkout to a point between > > > > > these 2 tags for many times manually and kernel always paniced.> > > > > > > > Where is the kernel panicing? The changeset right after the last one > > > > above: bc87d2fe7a1190f1c257af8a91fc490b1ee35954, is a change to efivars, > > > > are you using that in your .config?> > > > > > > > > All patches between the 2 tags are on kobject restructure. I guess such restructure > > > > > creates more cache miss on the 16-core tigerton.> > > > > > > > Nothing should be creating kobjects on a normal load like this, so a > > > > regression seems very odd. Unless the /sys/kernel/uids/ stuff is > > > > triggering this?> > > > > > > > Do you have a link to where I can get hackbench (google seems to find > > > > lots of reports with it, but not the source itself), so I can test to > > > > see if we are accidentally creating kobjects with this load?> > > > > > The version that I see referenced most often (unscientifically :) > > > is somewhere under people.redhat.com/mingo/, like so: > > > http://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c> > > > Great, thanks for the link.> > > > In using that version, I do not see any kobjects being created at all > > when running the program. So I don't see how a kobject change could > > have caused any slowdown.> > > > Yanmin, is the above link the version you are using?> Yes.> > > > > Hm, running with "hackbench 100 process 2000" seems to lock up my > > laptop, maybe I shouldn't run 4000 tasks at once on such a memory > > starved machine...> The issue doesn't exist on my 8-core stoakley and on tulsa. So I don't think > you could reproduce it on laptop. But I should see any kobjects being created and destroyed as you are thinking that is the problem here, right? And I don't see any, so I'm thinking that this is probably something else. I'm still interested in why your machine was oopsing when bisecting through the kobject commits. I thought it all should have worked without problems, as I spend enough time trying to ensure it was so... thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
| Last update: 2008-03-14 06:03 [from the cache] ©2003-2008 | ||||||||||