Re: Early SPECWeb99 results on 2.5.33 with TSO on e1000

So if i understood correctly (looking at the intel site) the main value
add of this feature is probably in having the CPU avoid reassembling and
retransmitting.

Quoting David S. Miller:

dsm> The performance improvement comes from the fact that the card
dsm> is given huge 64K packets, then the card (using the given ip/tcp
dsm> headers as a template) spits out 1500 byte mtu sized packets.
dsm> 
dsm> Less data DMA'd to the device per normal-mtu packet and less
dsm> per-packet data structure work by the cpu is where the improvement
dsm> comes from.

Do you have any stats from the hardware that could show
retransmits etc;

  I'll gather netstat -s after runs with and without TSO enabled.
Anything else you'd like to see?

have you tested this with zero copy as well (sendfile)

  Yes.  My webserver is Apache 2.0.36, which uses sendfile for anything
over 8k in size.  But, iirc, Apache sends the http headers using writev.

Thanks,

- Troy

Quoting Troy Wilson [off-list ref]:

quoted

Do you have any stats from the hardware that could show
retransmits etc;

  I'll gather netstat -s after runs with and without TSO enabled.
Anything else you'd like to see?

Troy, this is pointing out the obvious, but make sure
you have the before stats as well :)...

quoted

have you tested this with zero copy as well (sendfile)

  Yes.  My webserver is Apache 2.0.36, which uses sendfile for
anything
over 8k in size.  But, iirc, Apache sends the http headers using
writev.

SpecWeb99 doesnt execute the path that might benefit the 
most from this patch - sendmsg() of large files - large writes
going down..

thanks,
Nivedita

Nivedita Singhvi wrote:

SpecWeb99 doesnt execute the path that might benefit the 
most from this patch - sendmsg() of large files - large writes
going down..

For those of you who don't know Specweb well, the average size of a request 
is about 14.5 kB.  The largest files are ~5mb, but the largest top out at 
just under a meg.

-- 
Dave Hansen
haveblue@us.ibm.com