On 05/02/2013 12:58 PM, Alan Mackenzie wrote:
> On Thu, May 02, 2013 at 12:33:37PM -0400, Michael Mol wrote:
>> On 05/02/2013 12:27 PM, Alan Mackenzie wrote:
>>> Hi, Gentoo.
> 
>>> I've just built libreoffice-3.6.6.2 and it took 2 hours 10
>>> minutes on my 2.6 GHz quad core Athlon 2.  It used to take about
>>> an hour.
> 
>>> Watching the build, it became evident that the first 50 minutes
>>> or so was taken up by several hundred mkdir operations (more
>>> precisely, mkdir -p <long path>).  Some of these mkdir's would
>>> take, perhaps, a minute to execute.  All the while, top showed
>>> make taking 100% of one core.
> 
>>> There seems to be something suboptimal here.  Has anybody else
>>> seen this, or does anybody have any ideas how to fix the
>>> problem?
> 
>> Long delays suggest a timeout of some sort.
> 
> OK.  As a matter of interest, some of the mkdirs executed relatively 
> quickly - perhaps in 0.5 seconds.  I never saw the screen whizzing by
> as I ought to have done, though.

Hm.

> 
>> First thing I'd look at is the filesystem underneath, and the disk 
>> underneath that.
> 
> My /var is an ext3 LVM partition, doubled up on a RAID-1 disk array.

How full is the ext3 partition? What options do you have enabled on it?
(e.g. dir indexing?)


> In the middle of the mkdiring, I checked there were enough inodes
> free (there were).  I've no reason to suspect the disk drives might
> be flaky.

Well, you kinda do, now; you have evidence that at least some disk
access is unusually slow. Check dmesg for disk I/O errors (unlikely to
be reported at this point; I'm sure you checked whether your RAID was in
a degraded state), and run commanded smartctl tests on the disks.

> 
>> Second thing I'd look at is to see if permissions checks might be 
>> bouncing through something like kerberos, samba or ldap. Do you
>> have any single-signon things configured on that machine?
> 
> I've not got kerberos or samba installed.  I appear to have ldap 
> (whatever that might be ;-).  ls -lurt /usr/bin/ldap* shows these 
> binaries were last accessed (?used) on 2012-03-14.

It would be more a question of whether they were tied into PAM.

> 
> What exactly do you mean by "single-signon"?

Well, that was a slip of the tongue. More "central auth". I was
wondering if there were any features installed on your system that are
designed to check authorization against a server somewhere. (i.e. you
can use an LDAP directory to centrally manage things like users, groups,
etc.)

Technically, single-signon combines authorization checks with persistent
authentication checks. Examples of this include kerberos, web session
cookies and some uses of OAuth; once you're authenticated, the mechanism
ensures you don't need to authenticate to another server in the same
auth realm so long as your existing session hasn't expired. But this is
less likely to be related to your problem than something seeking to ask
a server if you have authorization to access something.