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Commit 5de22343 authored by Maciej Sosnowski's avatar Maciej Sosnowski Committed by Dan Williams
Browse files

I/OAT: set tcp_dma_copybreak to 256k for I/OAT ver.3 



Upcoming server platforms from Intel based on the Nehalem performance
have significantly improved CPU based copy performance.
However, the DMA engine can still be effective at higher I/O sizes
for TCP traffic and at this time copybreak
should be set to 256k for TCP traffic only.

Signed-off-by: default avatarMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: default avatarShannon Nelson <shannon.nelson@intel.com>
Acked-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 2b8a6bf8

drivers/dma/ioatdma.h

+3 −1
Original line number Diff line number Diff line
@@ -135,12 +135,14 @@ static inline void ioat_set_tcp_copy_break(struct ioatdma_device *dev) 
	#ifdef CONFIG_NET_DMA

	switch (dev->version) {

	case IOAT_VER_1_2:

	case IOAT_VER_3_0:

		sysctl_tcp_dma_copybreak = 4096;

		break;

	case IOAT_VER_2_0:

		sysctl_tcp_dma_copybreak = 2048;

		break;

	case IOAT_VER_3_0:

		sysctl_tcp_dma_copybreak = 262144;

		break;

	}

	#endif

}