Re: [PATCH v2 3/3] scsi/ncr5380: Improve interrupt latency during PIO tranfers
From: Martin K. Petersen
Date: Wed Sep 14 2016 - 14:12:48 EST
>>>>> "Finn" == Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx> writes:
Finn> Large PIO transfers are broken up into chunks to try to avoid
Finn> disabling local IRQs for long periods. But IRQs are still disabled
Finn> for too long and this causes SCC FIFO overruns during serial port
Finn> transfers.
Finn> This patch reduces the PIO chunk size to reduce interrupt latency
Finn> to something on the order of milliseconds, at the expense of
Finn> additional CPU overhead from extra iterations of the
Finn> NCR5380_main() loop.
Applied to 4.9/scsi-queue.
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Martin K. Petersen Oracle Linux Engineering