On Mon, Aug 28, 2017 at 08:30:24PM +0530, Sricharan R wrote: > The bam dmaengine has a circular FIFO to which we > add hw descriptors that describes the transaction. > The FIFO has space for about 4096 hw descriptors. > > Currently we add one descriptor and wait for it to > complete with interrupt and then add the next pending > descriptor. In this way, the FIFO is underutilized > since only one descriptor is processed at a time, although > there is space in FIFO for the BAM to process more. > > Instead keep adding descriptors to FIFO till its full, > that allows BAM to continue to work on the next descriptor > immediately after signalling completion interrupt for the > previous descriptor. > > Also when the client has not set the DMA_PREP_INTERRUPT for > a descriptor, then do not configure BAM to trigger a interrupt > upon completion of that descriptor. This way we get a interrupt > only for the descriptor for which DMA_PREP_INTERRUPT was > requested and there signal completion of all the previous completed > descriptors. So we still do callbacks for all requested descriptors, > but just that the number of interrupts are reduced. > > CURRENT: > > ------ ------- --------------- > |DES 0| |DESC 1| |DESC 2 + INT | > ------ ------- --------------- > | | | > | | | > INTERRUPT: (INT) (INT) (INT) > CALLBACK: (CB) (CB) (CB) > > MTD_SPEEDTEST READ PAGE: 3560 KiB/s > MTD_SPEEDTEST WRITE PAGE: 2664 KiB/s > IOZONE READ: 2456 KB/s > IOZONE WRITE: 1230 KB/s > > bam dma interrupts (after tests): 96508 > > CHANGE: > > ------ ------- ------------- > |DES 0| |DESC 1 |DESC 2 + INT | > ------ ------- -------------- > | > | > (INT) > (CB for 0, 1, 2) > > MTD_SPEEDTEST READ PAGE: 3860 KiB/s > MTD_SPEEDTEST WRITE PAGE: 2837 KiB/s > IOZONE READ: 2677 KB/s > IOZONE WRITE: 1308 KB/s > > bam dma interrupts (after tests): 58806 Applied, thanks. Sorry for the delay, bad timing I guess :) -- ~Vinod -- 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
