[E1000-devel] a question about ioatdma

[lixiaodong0807 <lix...@12...>]

 Hi!
    I am trying to use ioatdma feature in linux 2.6.23.My NIC is intel 82575.In order to use ioatdma ,i run the command :"modprobe ioatdma".
    I tune the sysctl "net.ipv4.tcp_dma_copybreak" to 1; "net.ipv4.tcp_timestamps" to 0;"tcp_low_latency" to 0.
   but I find that the channel 0-3 's bytes_transferred counter doesn't changed during I download a 635M file using wget.
 
before download: 

[root@localhost data0]# cat /sys/class/dma/dma0chan0/bytes_transferred
0
[root@localhost data0]# cat /sys/class/dma/dma0chan1/bytes_transferred
17068
[root@localhost data0]# cat /sys/class/dma/dma0chan2/bytes_transferred
0
[root@localhost data0]# cat /sys/class/dma/dma0chan3/bytes_transferred
2056

[root@localhost data0]# wget http://*.*.*.*:8080/CentOS-4.6-x86_64-bin1of4.iso
--00:07:57--  http://*.*.*.*::8080/CentOS-4.6-x86_64-bin1of4.iso
Connecting to *.*.*.*::8080... connected.
HTTP request sent, awaiting response... 200 OK
Length: 665802752 (635M) [application/octet-stream]
Saving to: `CentOS-4.6-x86_64-bin1of4.iso.15'

100%[===========================================================>] 665,802,752 85.8M/s   in 7.2s   

00:08:04 (88.1 MB/s) - `CentOS-4.6-x86_64-bin1of4.iso.15' saved [665802752/665802752]
after download
[root@localhost data0]# cat /sys/class/dma/dma0chan0/bytes_transferred
0
[root@localhost data0]# cat /sys/class/dma/dma0chan1/bytes_transferred
17068
[root@localhost data0]# cat /sys/class/dma/dma0chan2/bytes_transferred
0
[root@localhost data0]# cat /sys/class/dma/dma0chan3/bytes_transferred
2056 

I want to know why bytes_transferred is not increased ? (I tried to lower net.ipv4.tcp_dma_copybreak to 0, or use default value -4096,but it doesn't take effect")

Thank You!

the following is some information of my system

[root@localhost data0]# modinfo igb
filename:       /lib/modules/2.6.23/kernel/drivers/net/igb/igb.ko
version:        1.2.18.4
[root@localhost data0]# modinfo ioatdma
filename:       /lib/modules/2.6.23/kernel/drivers/dma/ioatdma.ko
author:         Intel Corporation
license:        GPL
version:        1.9

[root@localhost data0]# lspci
00:00.0 Host bridge: Intel Corporation 5000X Chipset Memory Controller Hub (rev 12)
00:02.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x4 Port 2 (rev 12)
00:03.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x4 Port 3 (rev 12)
00:04.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x8 Port 4-5 (rev 12)
00:05.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x4 Port 5 (rev 12)
00:06.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x8 Port 6-7 (rev 12)
00:07.0 PCI bridge: Intel Corporation 5000 Series Chipset PCI Express x4 Port 7 (rev 12)
00:08.0 System peripheral: Intel Corporation 5000 Series Chipset DMA Engine (rev 12)
00:10.0 Host bridge: Intel Corporation 5000 Series Chipset FSB Registers (rev 12)
00:10.1 Host bridge: Intel Corporation 5000 Series Chipset FSB Registers (rev 12)
00:10.2 Host bridge: Intel Corporation 5000 Series Chipset FSB Registers (rev 12)
00:11.0 Host bridge: Intel Corporation 5000 Series Chipset Reserved Registers (rev 12)
00:13.0 Host bridge: Intel Corporation 5000 Series Chipset Reserved Registers (rev 12)
00:15.0 Host bridge: Intel Corporation 5000 Series Chipset FBD Registers (rev 12)
00:16.0 Host bridge: Intel Corporation 5000 Series Chipset FBD Registers (rev 12)
00:1c.0 PCI bridge: Intel Corporation 631xESB/632xESB/3100 Chipset PCI Express Root Port 1 (rev 09)
00:1d.0 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #1 (rev 09)
00:1d.1 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #2 (rev 09)
00:1d.2 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #3 (rev 09)
00:1d.3 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB Controller #4 (rev 09)
00:1d.7 USB Controller: Intel Corporation 631xESB/632xESB/3100 Chipset EHCI USB2 Controller (rev 09)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev d9)
00:1f.0 ISA bridge: Intel Corporation 631xESB/632xESB/3100 Chipset LPC Interface Controller (rev 09)
00:1f.1 IDE interface: Intel Corporation 631xESB/632xESB IDE Controller (rev 09)
01:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 1078 (rev 04)
02:00.0 PCI bridge: Broadcom EPB PCI-Express to PCI-X Bridge (rev c3)
03:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12)
04:00.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Upstream Port (rev 01)
04:00.3 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express to PCI-X Bridge (rev 01)
05:00.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E1 (rev 01)
05:01.0 PCI bridge: Intel Corporation 6311ESB/6321ESB PCI Express Downstream Port E2 (rev 01)
06:00.0 PCI bridge: Broadcom EPB PCI-Express to PCI-X Bridge (rev c3)
07:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12)
0a:00.0 PCI bridge: Integrated Device Technology, Inc. Unknown device 8018 (rev 0e)
0b:02.0 PCI bridge: Integrated Device Technology, Inc. Unknown device 8018 (rev 0e)
0b:04.0 PCI bridge: Integrated Device Technology, Inc. Unknown device 8018 (rev 0e)
0c:00.0 Ethernet controller: Intel Corporation 82575GB Gigabit Network Connection (rev 02)
0c:00.1 Ethernet controller: Intel Corporation 82575GB Gigabit Network Connection (rev 02)
0d:00.0 Ethernet controller: Intel Corporation 82575GB Gigabit Network Connection (rev 02)
0d:00.1 Ethernet controller: Intel Corporation 82575GB Gigabit Network Connection (rev 02)
11:0d.0 VGA compatible controller: ATI Technologies Inc ES1000 (rev 02)