On 10/21/2015 9:27 AM, Mark Brown wrote: > On Wed, Oct 21, 2015 at 08:59:51AM -0700, Frank Rowand wrote: >> On 10/19/2015 5:34 AM, Tomeu Vizoso wrote: > >>> To be clear, I was saying that this series should NOT affect total >>> boot times much. > >> I'm confused. If I understood correctly, improving boot time was >> the key justification for accepting this patch set. For example, >> from "[PATCH v7 0/20] On-demand device probing": >> >> I have a problem with the panel on my Tegra Chromebook taking longer >> than expected to be ready during boot (Stéphane Marchesin reported what >> is basically the same issue in [0]), and have looked into ordered >> probing as a better way of solving this than moving nodes around in the >> DT or playing with initcall levels and linking order. >> >> ... >> >> With this series I get the kernel to output to the panel in 0.5s, >> instead of 2.8s. > > Overall boot time and time to get some individual built in component up > and running aren't the same thing - what this'll do is get things up > more in the link order of the leaf consumers rather than deferring those > leaf consumers when their dependencies aren't ready yet. Thanks! I read too much into what was being improved. So this patch series, which on other merits may be a good idea, is as a by product solving a specific ordering issue, moving successful panel initialization to an earlier point in the boot sequence, if I now understand more correctly. In that context, this seems like yet another ad hoc way of causing the probe order to change in a way to solves one specific issue? Could it just as likely move the boot order of some other driver on some other board later, to the detriment of somebody else? > >> While not as dramatic as your results, they are somewhat supportive. >> What has changed your assessment that the on-demand device probing >> patches will give a big boot performance increase? Do you have >> new data or analysis? > > See above, my understanding was that the performance improvements were > more around improved control/predictability/handwave of the boot > ordering rather than total time. > -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
