Messages in this thread | | | From | Peter Ujfalusi <> | Subject | [PATCH 0/4] dmaengine: omap-dma: transfer start and short memcpy improvement | Date | Wed, 11 Nov 2015 12:37:54 +0200 |
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Hi,
The first two patch is trivial fix. The third (remove the tasklet use for starting the transfer): I had been wondering about this for a while and now I was able to spend some time to look at this in more detail. In 'normal' operation I have never seen the tasklet to start more then one transfer even when pushing I/O based workloads on the board. However when I run the DMAtest module I can see that the tasklet executes about 15 transfers. When the tasklet use has been removed, everything worked as well as before but the throughput of MMC/SD and memcpy increased slightly:
dd if=/dev/mmcblk0 of=/dev/null bs=64k count=24000 ~16.5 MB/s -> ~16.6 MB/s
echo 6553 > /sys/module/dmatest/parameters/test_buf_size echo 2000 > /sys/module/dmatest/parameters/timeout echo 5000 > /sys/module/dmatest/parameters/iterations ~585 KB/s -> ~638 KB/s
It worth mentioning that _with_ the tasklet starting the transfers I managed to hit a situation once when for some reason the memcpy tests were started to time out. This happend with memcpy, iozone, dd and grep -R blabla /usr/ running at the same time.
The last patch is to correct the behaviour of omap-dma when short memcpy is used by a client and the client is not using completion, but polling for the end of the transfer.
Regards, Peter --- Peter Ujfalusi (4): dmaengine: omap-dma: Correct status reporting for memcpy dmaengine: omap-dma: Clean up the prep_slave_sg sg list walk code dmaengine: omap-dma: Remove tasklet to start the transfers dmaengine: omap-dma: Handle cases when the channel is polled for completion
drivers/dma/omap-dma.c | 78 +++++++++----------------------------------------- 1 file changed, 14 insertions(+), 64 deletions(-)
-- 2.6.2
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