Re: [RFC] [PATCH v2 00/11] Optimize spi_sync path

[David Jander <david@xxxxxxxxxxx>]

On Wed, 15 Jun 2022 15:31:13 +0200
Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> wrote:

> On 15.06.2022 14:46:23, David Jander wrote:
> > These patches optimize the spi_sync call for the common case that the
> > worker thread is idle and the queue is empty. It also opens the
> > possibility to potentially further optimize the async path also, since
> > it doesn't need to take into account the direct sync path anymore.
> > 
> > As an example for the performance gain, on an i.MX8MM SoC with a SPI CAN
> > controller attached (MCP2518FD), the time the interrupt line stays
> > active (which corresponds roughly with the time it takes to send 3
> > relatively short consecutive spi_sync messages) is reduced from 98us to
> > only 72us by this patch.
> > 
> > A note about message ordering:
> > 
> > This patch series should not change the behavior of message ordering when
> > coming from the same context. This means that if a client driver issues
> > one or more spi_async() messages immediately followed by a spi_sync()
> > message in the same context, it can still rely on these messages being
> > sent out in the order they were fired.  
> 
> Which git branch to use as the base?

Sorry, forgot to mention: spi for-next:
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git

This is because it relies on previous patches that have been applied there.

-- 
David Jander