Low network throughput on i.MX28

[Jörg Krause]

On Sat, 2016-11-05 at 12:39 +0000, Koul, Vinod wrote:
> On Sat, 2016-11-05 at 13:06 +0100, Jörg Krause wrote:
> > @ Vinod
> > In short, I noticed poor performance in the SSP2 (MMC/SD/SDIO)
> > interface on a custom i.MX28 board with a wifi chip attached.
> > Comparing
> > the bandwith with iperf I get >20Mbits/sec on the vendor kernel and
> > <5Mbits/sec on the mainline kernel. I am trying to investigate what
> > the
> > bottleneck is.
> 
> is this imx-dma or imx-sdma..
> 
> > 
> > @ Stefan, all
> > My understanding is that the tasklet in this case is responsible
> > for
> > reading the response registers of the DMA controller and return the
> > response to the MMC host driver.
> > 
> > The vendor kernel does this in the interrupt routine of mxs-mmc by
> > issueing a complete whereas the mainline kernel does this in the
> > interrupt routine in mxs-dma by scheduling the tasklet.
> 
> Is vendor kernel using dmaengine APIs or not?

It's this engine [1].

[1] http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/ar
ch/arm/plat-mxs/dmaengine.c?h=imx_2.6.35_1.1.0