Re: [gentoo-user] Re: [OT] fast recursive local copy

[Volker Armin Hemmann <volkerarmin@googlemail.com>]

On Samstag 15 August 2009, Dirk Heinrichs wrote:
> Am Freitag 14 August 2009 22:47:46 schrieb Joerg Schilling:
> > Dirk Heinrichs <dirk.heinrichs@online.de> wrote:
> > > Am Freitag 14 August 2009 10:50:45 schrieb Joerg Schilling:
> > > > Note that on Linux you may need to add "-no-fsync" because file I/O
> > > > is slow on Linux. On Solaris, not using -no-fsync slows things down
> > > > by aprox. 10% but allows star to grant that everything was really
> > > > copied to stable storage. On Linux, ot using -no-fsync slows things
> > > > down by aprox. 400%, this is why I recommend to add "-no-fsync".
> > >
> > > This is also quite interesting. Do you have some (links to) recent
> > > benchmarks which would second that? Could this even be depending on the
> > > filesystem used on Linux?
> >
> > I did this test aprox. 3-4 years ago. You may try to do an own test and
> > report.
> >
> > I did just rerun a test on a recent ubuntu in a VirtualBox environment
> > and the speedup factor with -no-fsync was 8x.
>
> OK, here's mine, then. Please note that the test happened on an encrypted
> logical volume containing an XFS filesystem. Source and destination
> directory are on the same LV.
>
> # time star -copy -p -xdot -acl -sparse -C /gentoo/overlays/portage .
> /gentoo/build/portage
> star: 0 blocks + 447532544 bytes (total of 447532544 bytes = 437043.50k).
> star -copy -p -xdot -acl -sparse -C /gentoo/overlays/portage .   16,57s
> user 60,22s system 11% cpu 11:23,63 total
>
> # time star -copy -p -xdot -acl -sparse -no-fsync -C
> /gentoo/overlays/portage . /gentoo/build/portage
> star: 0 blocks + 447532544 bytes (total of 447532544 bytes = 437043.50k).
> star -copy -p -xdot -acl -sparse -no-fsync -C /gentoo/overlays/portage .
> 12,33s user 35,39s system 10% cpu 7:44,13 total
>
> Unfortunately, I can't compare with OSol :(
>
> Bye...
>
> 	Dirk

and you dropped caches in between?