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ioatdma: Push pending transactions to hardware more frequently 

Every 20 descriptors turns out to be to few append commands with
newer/faster CPUs.  Pushing every 4 still cuts down on MMIO writes to an
acceptable level without letting the DMA engine run out of work.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
This commit is contained in:
Chris Leech 2007-03-08 09:57:33 -08:00 committed by Dan Williams
parent 7dcca30a32
commit 000725d56a
1 changed files with 2 additions and 2 deletions
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4
drivers/dma/ioatdma.c
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@ -310,7 +310,7 @@ static dma_cookie_t do_ioat_dma_memcpy(struct ioat_dma_chan *ioat_chan,
list_splice_init(&new_chain, ioat_chan->used_desc.prev);
ioat_chan->pending += desc_count;
if (ioat_chan->pending >= 20) {
if (ioat_chan->pending >= 4) {
append = 1;
ioat_chan->pending = 0;
}
@ -818,7 +818,7 @@ static void __devexit ioat_remove(struct pci_dev *pdev)
}
/* MODULE API */
MODULE_VERSION("1.7");
MODULE_VERSION("1.9");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Intel Corporation");