Re: fc5 kernels after 1788 have excessive, kernel overhead

[Anne & Lynn Wheeler <lynn garlic com>]

> Will this hit a system with EXT3->LVM->MDRAID1 particularly hard? Took
> about two hours to do a local install (with a largish set of packages
> but not everything) which I seem to remember took about 3/4 of an hour
> before.
>
> During installation ext3_xattr_block_set and r1bio_pool_alloc show as
> the top guzzlers, totalling 1.5 billion allocations between them,
> obviously plenty of disk writing going on ...

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

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).