[PATCH 1/7] [I/OAT] Push pending transactions to hardware more frequently
From: Chris Leech <hidden>
Date: 2006-08-16 00:45:51
Also in:
lkml
Subsystem:
dma generic offload engine subsystem, intel i/oat dma driver, the rest · Maintainers:
Vinod Koul, Dave Jiang, Linus Torvalds
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 <redacted> --- drivers/dma/ioatdma.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/ioatdma.c b/drivers/dma/ioatdma.c
index dbd4d6c..be4fdd7 100644
--- a/drivers/dma/ioatdma.c
+++ b/drivers/dma/ioatdma.c@@ -310,7 +310,7 @@ static dma_cookie_t do_ioat_dma_memcpy(s 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 } /* MODULE API */ -MODULE_VERSION("1.7"); +MODULE_VERSION("1.9"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Intel Corporation");