TCP/UDP cksum offload on hme(4)

Pyun YongHyeon yongari at
Wed Jun 16 03:59:44 GMT 2004

On Wed, Jun 16, 2004 at 12:45:20PM +0900, To freebsd-sparc64 at wrote:
 > Hello All,
 > I made a patch that enables cksum offloads on hme(4). Originally
 > the patch was made for OpenBSD due to FreeBSD's lack of FAS366
 > support. Now, we had esp(4) ported by Scott, I could port the patch
 > from my OpenBSD patch. During simple test phase, I didn't notice
 > problems. 
 >  1. UDP TX cksum offload has an issue. The hardware doesn't flip the
 >     cksum bits when the computed cksum is 0x0000. I have no idea this
 >     is the reason why STP2002QFP says it supports only TCP RX/TX cksum.
 >     (pp. 29, pp. 40, pp. 42)
 >  2. The patch was tested on Ultra2(2x300MHz, FAS366). I'd like to
 >     hear ok/nok results from PCI based sparc64 users.
 >     The dmesg of the Ultra2 is available at:
 >     http:///
 >  3. I couldn't feel performance boost from the cksum offloads but
 >     enabling it reduced system loads considerably.
 > The attached patch is for -CURRENT(2004.06.07), and is also available at:
                                      ^^^^^^^^^^^ 2004.06.14
The corrected URL is:

Pyun YongHyeon <>

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