Date: Sun, 24 Sep 2006 18:23:41 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Tim Kientzle <tim@kientzle.com> Cc: src-committers@FreeBSD.org, Andre Oppermann <andre@FreeBSD.org>, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org, Tim Kientzle <kientzle@FreeBSD.org>, Ruslan Ermilov <ru@FreeBSD.org>, Kris Kennaway <kris@obsecurity.org> Subject: Re: bsdtar vs gtar performance Message-ID: <20060924165852.O74016@delplex.bde.org> In-Reply-To: <45156E4E.6040806@kientzle.com> References: <200609150804.k8F84O1H056038@repoman.freebsd.org> <20060915155912.GA71796@xor.obsecurity.org> <450AD508.10608@freebsd.org> <20060915180315.GB74735@xor.obsecurity.org> <450C30ED.7090901@freebsd.org> <20060916192437.GA15425@xor.obsecurity.org> <45156E4E.6040806@kientzle.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, 23 Sep 2006, Tim Kientzle wrote: > Kris and Ruslan were recently discussing the performance of bsdtar > relative to gtar, which prompted me to do some measurements > of my own. I used /usr/ports as my test, because it stresses > file and directory creation over extracting large files. > > Here are some initial results, based on ten runs of each test on a > quiescent system, comparing results with PHK's "ministat": > > [... ones with no difference] > > * Extracting uncompressed archives: gtar is about 13% faster > than bsdtar in my test. Interestingly (to me), this was the same > with or without -m. (I've long suspected dir timestamp restores > as a contributor; this shows otherwise.) Changes to attributes by syscalls (utimes(), chown()... are always written asynchronously, so -m should always have little effect. A quick test showed that the main difference for extraction is that bsdtar does an lchmod() for every file extracted. gtar apparently optimizes away null chmod()'s. I would expect -m to make little difference for bsdtar since the writes for the changes to the attributes from utimes() + lchmod() are coalesced, but for gtar -m would be noticeable faster since it usually eliminates these writes. Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20060924165852.O74016>