Re: 2.6.12-rc2-mm1

Nick Piggin
2005-04-05T23:42:31Z

Siddha, Suresh B wrote:
> On Tue, Apr 05, 2005 at 05:33:49PM +1000, Nick Piggin wrote:

>>Suresh's underlying problem with the unnecessary sched domains
>>is a failing of sched-balance-exec and sched-balance-fork, which
>
>
> That wasn't the only motivation. For example, on non-HT cpu's we shouldn't
> be setting up SMT sched-domain, same with NUMA domains on non-NUMA systems.
>

Yep, sure. It is a good, if slight, optimisation. And I've also just
slightly extended your patch, so we don't have any domains if booting
with maxcpus=1

>
>>I am working on now.
>>
>>Removing unnecessary domains is a nice optimisation, but just
>>needs to account for a few more flags before declaring that a
>
>
> Can you elaborate when we require a domain with special flags but has
> no or only one group in it.
>

The SD_WAKE_* flags do not use groups, so it would be legitimate to
have a domain that has one of these set, with no groups.

>
>>domain is unnecessary (not to mention this probably breaks if
>>isolcpus= is used). I have made some modifications to the patch
>
>
> I have tested my patch with "ioslcpus=" and it works just fine.
>

OK, my apologies ;)

>
>>to fix these problems.
>>
>>Lastly, I'd like to be a bit less intrusive with pinned task
>>handling improvements. I think we can do this while still being
>>effective in preventing livelocks.
>
>
> We want to see this fixed. Please post your patch and I can let you know
> the test results.
>

I will try to get it working and tested tonight for you.

>
>>I will keep you posted with regards to the various scheduler
>>patches.
>
>
> Nick, Can you post the patches you sent me earlier to this list?
>

Yep, I'll post them.

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