Messages in this thread | | | Date | Wed, 25 Oct 2000 12:41:25 -0600 | From | "Jeff V. Merkey" <> | Subject | Re: [PATCH] Re: PATCH: killing read_ahead[] |
| |
Rik van Riel wrote: > > On Wed, 25 Oct 2000, Jeff V. Merkey wrote: > > > I've reviewed the patch. It's affect seems minimal and will not > > break NWFS as proposed -- it looks like, however, it will reduce > > the performance slightly of EXT2/3 with iozone for read ahead > > since the first section of the patch limits the read ahead > > window size. > > Ummm, please read it again ;) > > The patch actually /increases/ the readahead size when > we start to read a file from the beginning.
But only if the file is smaller than MIN_READAHEAD * 2, which would be the case for small files (which would read the whole file anyway, which is how the page cache behaves today anyway).
?* If we start reading from the beginning of the file, read in MIN_READAHEAD pages. Note that if the file is smaller then MIN_READAHEAD * 2 limiting ourselves to MIN_READAHEAD would result in one "too small" IO
(there's that fixed block size crap biting us in the ass again)
so in that case, just read the whole file.
:-)
Jeff
> > regards, > > Rik > -- > "What you're running that piece of shit Gnome?!?!" > -- Miguel de Icaza, UKUUG 2000 > > http://www.conectiva.com/ http://www.surriel.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
| |