Messages in this thread | | | Date | Fri, 06 Jan 2006 16:45:05 +0000 | From | Shailabh Nagar <> | Subject | Re: [Lse-tech] Re: [ckrm-tech] Re: [PATCH 00/01] Move Exit Connectors |
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Jes Sorensen wrote: >>>>>>"Matt" == Matt Helsley <matthltc@us.ibm.com> writes: > > > Matt> Right. I forgot to repeat what I mentioned in the parent email > Matt> -- that this patch is intended to be applied on top of > Matt> Shailabh's patches. > > Matt> The first patch I posted (01/01) is intended for plain > Matt> 2.6.15. Before proposing 01/01 for -mm I've been trying to see > Matt> if there are any problems with the value of tsk->exit_signal > Matt> before exit_mm() -- hence the "[RFC]" in the subject line of > Matt> that one. > > Matt, > > Any chance one of you could put up a set of current patches somewhere?
I'll upload the delay accounting patches to a newly created lse-tech package.
> I am trying to make heads and tails of them and it's pretty hard as I > haven't been on lse-tech for long and the lse-tech mailing list > archives are useless due to the 99 to 1 SPAM ratio ;-( >
> I am quite concerned about that lock your patches put into struct > task_struct through struct task_delay_info. Have you done any > measurements on how this impacts performance on highly threaded apps > on larger system?
I don't expect the lock contention to be high. The lock is held for a very short time (across two additions/increments). Moreover, it gets contended only when the stats are being read (either through /proc or connectors). Since the reading of stats won't be that frequent (the utility of these numbers is to influence the I/O priority/rss limit etc. which won't be done at a very small granularity anyway), I wouldn't expect a problem.
But its better to take some measurements anyway. Any suggestions on a benchmark ?
> IMHO it seems to make more sense to use something like Jack's proposed > task_notifier code to lock-less collect the data into task local data > structures and then take the data from there and ship off to userland > through netlink or similar like you are doing? > > I am working on modifying Jack's patch to carry task local data and > use it for not just accounting but other areas that need optional > callbacks (optional in the sense that it's a feature that can be > enabled or disabled). Looking at Shailabh's delayacct_blkio() changes > it seems that it would be really easy to fit those into that > framework. > > Guess I should post some of this code .....
Please do. If this accounting can fit into some other framework, thats fine too.
-- Shailabh
> Cheers, > Jes >
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