yum 3.2.23 more than 10x slower than 3.2.21?!

Roberto Ragusa mail at robertoragusa.it
Fri Jun 26 14:59:35 UTC 2009


Seth Vidal wrote:
> 3.2.23 is showing 3.186s for a yum list updates on my system
> 
> 3.2.21 is shwoing 3.339s for the same.

# time yum list updates
Loaded plugins: downloadonly
Updated Packages
[snipped list with 70-80 package]

real    1m28.537s
user    1m23.830s
sys     0m0.536s

# rpm -Uhv --oldpackage yum-3.2.21-2.fc10.noarch.rpm
Preparing...                ########################################### [100%]
   1:yum                    ########################################### [100%]
[root at thinkpad etc]# time yum list updates
Loaded plugins: downloadonly
Updated Packages
[snipped list with 70-80 package]

real    0m7.296s
user    0m6.549s
sys     0m0.324s

This is my yum.conf, where I justr added the last line, as you suggested.

[main]
cachedir=/var/cache/yum
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=3

It is really CPU intensive. I see some unicode related stuff in the changelog
and my memory goes to years ago (RedHat 8?) when the UTF8 enabled grep
got a similar slowdown (the lib was then improved after that).

Hmmmmm, made other experiments....
Really weird.

#time yum list updates --disablerepo=\* --enablerepo=ROB10\*
(less than 3 seconds)

#time yum list updates --disablerepo=\* --enablerepo=updates
(less than 3 seconds)

#time yum list updates --disablerepo=\* --enablerepo=ROB10\*  --enablerepo=updates
(more than one minute)

ROB10\* is some local repositories, containing mirrored stuff from some
repositories, _including fedora_updates_, so the same rpms are found in two
different repositories. How can this trigger such a slowdown, I don't know.

I have to correct what I said before, the time is not always spent
on read64() and gettimeofday(); there is a lot of strace-silent activity
(just spurious brk() calls).

Maybe something like hashing of some data structure is taking a really bad
direction?

-- 
   Roberto Ragusa    mail at robertoragusa.it




More information about the fedora-devel-list mailing list