On Tue, 13 Oct 2009, Paul Fulghum wrote: > On Tue, 2009-10-13 at 07:39 -0700, Linus Torvalds wrote: > > It's not a f*cking performance tweak, and you're ludicrous to claim it is. > > It's pointless, and it's making the code _slower_ rather than faster. > > > > Lookie here, Alan - the common sequence is crap like this: > > > > tty_buffer_request_room(tty, buf->size); > > tty_insert_flip_string(tty, buf->base, buf->size); > > The performance tweak of tty_prepare_xxx is that you fill > the tty_buffer directly instead of writing data first to a staging > buffer and then calling tty_insert_flip_string, which just copies > from the staging buffer to the tty_buffer. So it saves a copy operation. Read the above again. Read what that common sequence is. Please just READ the f*cking code, and read my emails, instead of talking about something totally different that I'm not talking about at all. The _most_common_ use of "tty_buffer_request_room()" is literally just the above insane sequence I quoted, not the case you talk about at all. Don't believe me? Use grep. What _you_ are talking about is something else, namely the tty_prepare_flip stuff. But dammit, that has nothing what-so-ever to do with "tty_buffer_request_room()". What I was pointing out is that there are a lot of "tty_buffer_request_room()" calls, and as far as I can see, all of them (or at least a large percentage) are just pure and utter crap. Linus -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
