[systemd-devel] Improve boot-time of systemd

[Lennart Poettering]

On Sat, 19.03.11 06:05, Chen Jie (chenj at lemote.com) wrote:

> 
> 2011/3/18 Kay Sievers <kay.sievers at vrfy.org>:
> > On Fri, Mar 18, 2011 at 14:40, Gustavo Sverzut Barbieri
> > <barbieri at profusion.mobi> wrote:
> >> On Fri, Mar 18, 2011 at 10:52 AM, Andrey Borzenkov <arvidjaar at mail.ru> wrote:
> >>> On Fri, Mar 18, 2011 at 12:35 PM, fykcee1 at gmail.com <fykcee1 at gmail.com> wrote:
> >
> >>>> 1. What can readahead affect boot-time?
> >>>> Sadly observed negative affect -- boot-time increases at least 1s.
> >>>
> >>> From subjective feelings (no real measurements) I confirm it.
> >>
> >> I noticed it as well, even with my Macbook Pro i7 with 8Gb RAM and
> >> 128SSD using btrfs.
> >
> > It's ~0.5 sec faster here with readahead on a SSD.
> Each time runs readahead-replay may cause readahead-collect to record
> more blocks to read ahead -- size of "/.readahead" never reduces.
> 
> Also I found "/.readahead" recorded files like ".xession-errors" which
> is written only, thus should not be read ahead.

Well, fanotify curently doesn't inform us whether open() was called for
O_RDONLY or O_RDWR/O_WRONLY. If it did we could ignore the latter.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.