IMX53 on recent 4.4.x kernels

[linux@armlinux.org.uk (Russell King - ARM Linux)]

On Fri, Jul 21, 2017 at 01:29:08PM -0300, Fabio Estevam wrote:
> Hi Russell,
> 
> On Thu, Jul 20, 2017 at 8:53 PM, Russell King - ARM Linux
> <linux@armlinux.org.uk> wrote:
> 
> > Another thing to check is that you have features like the spinlock
> > debug, semaphore debug, lockdep, tracing etc all disabled - these
> > can add quite a bit of additional processing into critical paths.
> 
> Yes, this really helps.
> 
> On my tests with Noel's application the execution time goes from 41 to
> 22 seconds on kernel 4.13-rc1.
> 
> Here is the defconfig changes generated by manually removing these
> features and then using savedefconfig:

Note - you want lockdep and so forth enabled for development kernels
to catch bugs before changes are submitted upstream.  However, for
kernels that you care about performance, you need to have them disabled.

Like everything it's a balance between function and performance.

-- 
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