Messages in this thread | | | Subject | Re: [PATCH v2 1/8] mmc: sdhci: Get rid of finish_tasklet | From | Adrian Hunter <> | Date | Mon, 25 Feb 2019 10:17:55 +0200 |
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On 15/02/19 9:20 PM, Faiz Abbas wrote: > sdhci.c has two bottom halves implemented. A threaded_irq for handling > card insert/remove operations and a tasklet for finishing mmc requests. > With the addition of external dma support, dmaengine APIs need to > terminate in non-atomic context before unmapping the dma buffers. > > To facilitate this, remove the finish_tasklet and move the call of > sdhci_request_done() to the threaded_irq() callback.
The irq thread has a higher latency than the tasklet. The performance drop is measurable on the system I tried:
Before:
# dd if=/dev/mmcblk1 of=/dev/null bs=1G count=1 & 1+0 records in 1+0 records out 1073741824 bytes (1.1 GB) copied, 4.44502 s, 242 MB/s
After:
# dd if=/dev/mmcblk1 of=/dev/null bs=1G count=1 & 1+0 records in 1+0 records out 1073741824 bytes (1.1 GB) copied, 4.50898 s, 238 MB/s
So we only want to resort to the thread for the error case.
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