Re: [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock

[Oleg Nesterov]

On 08/21, Peter Zijlstra wrote:
>
> The other consideration is that this adds two branches to the normal
> schedule path. I really don't know what the regular ratio between
> schedule() and io_schedule() is -- and I suspect it can very much depend
> on workload -- but it might be a net loss due to that, even if it makes
> io_schedule() 'lots' cheaper.

Yes, agreed. Please ignore it for now, I didn't try to actually suggest
this change. And even if this is fine perfomance wise, this needs some
benchmarking.

Well. actually I have a vague feeling that _perhaps_ this change can
help to solve other problems we are discussing, but I am not sure and
right now I can't even explain the idea to me.

In short: please ignore ;)

Oleg.

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