Messages in this thread | | | Date | Tue, 25 Feb 2014 12:29:16 +0000 | From | Russell King - ARM Linux <> | Subject | Re: Ideas/suggestions to avoid repeated locking and reducing too many lists with dmaengine? |
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On Mon, Feb 24, 2014 at 04:38:48PM -0600, Joel Fernandes wrote: > Actually I did do some tracing earlier before I posted this thread- and > notice there was excessive traces of locking/unlocking. It is very light > though as you pointed and lighter without debug options. The only other > notable difference is the fact that we are now going through the dmaengine > framework in the newer kernel vs the faster one.
Okay, for OMAP, there's additional latency caused by the tasklet which starts a transaction when there's no previous transaction running - that will be your biggest problem.
I do want to move omap-dma away from having a fixed binding between claimed channels and the logical channels since that's too wasteful, and that's what the tasklet will eventually be doing - but with omap-dma being divorsed from the old code, this tasklet may not be necessary anymore (since we no longer have to operate in process context for that bit.)
There's a huge pile of patches I have queued up for the next merge window in linux-next - I'd rather get these into mainline before trying to do any restructuring, otherwise we're going to get into a hell of a problem with merge conflicts.
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