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Re: dpkg 1.15.6 is slow as hell


Guillem Jover wrote:

> I implemented this and in my tests with linux-headers-2.6.32-4-common
> (which contains around 2500 files) on ext3 it reduced the installation
> times from 12~ to 5~ seconds (with warm cache).

I also get approx 50% speedup. [1]


 cold cache 14.46user 3.82system 1:20.01elapsed 22%CPU
 warm cache 14.34user 3.60system 1:14.72elapsed 24%CPU

v1.15.6 plus your patch:

 cold cache 14.44user 3.74system 0:39.51elapsed 46%CPU
 warm cache 14.32user 3.72system 0:34.24elapsed 53%CPU

v1.15.6 minus the fsync() added to src/archives.c in 62668eb:

 cold cache 14.28user 3.77system 0:38.03elapsed 47%CPU
 warm cache 14.39user 3.13system 0:25.26elapsed 69%CPU

> Could you guys test it on ext4, preferably on such systems which are
> taking now over an hour to unpack the package?

In the cold cache case (IMHO the case that matters), on this system
your patch appears to be about as fast as using no fsync() to unpack
at all.  Nice.


[1] /usr/bin/time sudo dpkg -i python2.5*_2.5.5-4_i386.deb

kernel: Linux 2.6.33-2-686 (Debian version 2.6.33-1~experimental.3)
filesystem: ext4 with data=ordered
disk: an old 4200 rpm 50 GiB laptop drive.
nothing interesting going on in the background.
all times are best of 3.

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