fc5 kernels after 1788 have excessive, kernel overhead

[Andy Burns]

Anne & Lynn Wheeler wrote:

> long running application doing enet to disk transfer sustains
> 2.6mbytes/sec transfer with 20% cpu busy (mostly non-kernel time).

Even that seems pretty low, I'd have thought you should be able to 
sustain 10-12MB/s

> post-1788 kernel, it is 100% cpu (mostly kernel time) and 600kbytes/sec
> sustained (an increase of over 20times in total cpu executed per byte
> transferred and possibly an increase of 100times in kernel cpu executed
> per byte transferred).

Just did a quick test here, a http wget of a 75MB file across a 100Mb/s 
full duplex link, where the file is fully cached on the source machine, 
I scrape 1.8MB/s and eat 75% CPU on a 3.0GHz HT P4, if I do some 
"intensive" monitoring with top, I can get it down to about 900KB/s

Of course we're not really proving anything here, we know that 
kernel1805 is built for debugging not for speed ...