Re: [take13 1/3] kevent: Core files.

Christoph Hellwig
2006-08-24T20:03:41Z

One question on the implementation of kevent_user_ctl_modify/
kevent_user_ctl_remove/kevent_user_ctl_add: What benchmarks did you
do to add the separate 'fastpath' with the single onstack ukevent
structure if there are three or less events? I can't believe this
actually helps in practice for various reasons:

- you add quite a lot of icache footprint by duplicating all this code
- kmalloc is really fast
- two or three small copy_from/to_user calls are quite a bit slower
than one that covers the size of all of them.