Xen users - Feb 2006 - Poor performance with openldap 2.3.x (Berkeley DB 4.3 or 4.4) on XEN 3.0.x

Dear all,

With or without /lib/tls librairies activated, A search in openldap is very slow
on XEN 3.0.x . Cpus do nothing .

15000 entries are dumped in 2 minutes whereas same search without xen are dumped
in 4 seconds (with far more activitie on CPUs)

I have already see one or mail about this problem .  But I don''t see a
solution , perhaps a threading problem between Berkeley DB and XEN ?

Versions used.

(Openldap 2.3.x)

(Berkeley DB 4.3 or 4.4)

Alexandre LABICHE 


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Hi Alexandre,

Have you disabled TLS or installed a Xen-friendly glibc? TLS will
cause performance problems om i686 unless disabled.


LABICHE Alexandre wrote:
>
> Dear all,
>
> With or without /lib/tls librairies activated, A search in openldap
>  is very slow on XEN 3.0.x . Cpus do nothing .
>
> 15000 entries are dumped in 2 minutes whereas same search without
> xen are dumped in 4 seconds (with far more activitie on CPUs)
>
> I have already see one or mail about this problem .  But I don''t
> see a solution , perhaps a threading problem between Berkeley DB
> and XEN ?
>
> Versions used.
>
> (Openldap 2.3.x)
>
> (Berkeley DB 4.3 or 4.4)
>
> Alexandre LABICHE
>
> ----------------------------------------------------------------------
>
>
> _______________________________________________ Xen-users mailing
> list Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users

- --
Per Andreas Buer
Linpro AS / Ledende på Linux i Norge
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Hi Per ,

Yes I have disabled TLS and there ''is no performance improvement. I am
on RHEL 4 Update 2 (great stability , on my opinion , far better than RHEL3 on
SMP computers ...)

and I don''t know exactly how to obtain a Xen-friendly glibc.  Sure
!!! it should be interesting to do this, because of the 30 times less
performance on openldap .

Alexandre LABICHE 

From: Per Andreas Buer 
To: LABICHE Alexandre 
CC: xen-users@lists.xensource.com
Subject: Re: [Xen-users] Poor performance with openldap 2.3.x (Berkeley DB 4.3
or 4.4) on XEN 3.0.x
Date: Sat, 04 Feb 2006 12:05:30 +0100
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
>Hi Alexandre,
>
>Have you disabled TLS or installed a Xen-friendly glibc? TLS will
>cause performance problems om i686 unless disabled.
>
>
>LABICHE Alexandre wrote:
> >
> > Dear all,
> >
> > With or without /lib/tls librairies activated, A search in
openldap
> > is very slow on XEN 3.0.x . Cpus do nothing .
> >
> > 15000 entries are dumped in 2 minutes whereas same search
without
> > 
xen are dumped in 4 seconds (with far more activitie on CPUs)
> >
> > I have already see one or mail about this problem . But I
don''t
> > see a solution , perhaps a threading problem between Berkeley
DB
> > and XEN ?
> >
> > Versions used.
> >
> > (Openldap 2.3.x)
> >
> > (Berkeley DB 4.3 or 4.4)
> >
> > Alexandre LABICHE
> >
> >
----------------------------------------------------------------------
> >
> >
> > _______________________________________________ Xen-users
mailing
> > list Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
>
>
>- --
>Per Andreas Buer
>Linpro AS / Ledende på Linux i Norge
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So after compiling from scratch a Xen-friendly glibc for rhel4U2.

From rpm redhat glibc source, after applying patchs and use following
compilation parameters

env CFLAGS="-O2 -mno-tls-direct-seg-refs" ../configure --prefix=/usr
--disable-profile --enable-add-ons --libexecdir=/usr/lib/glibc ; make ; make
check

I have an error with nanosleep() in "make check"  under a xenU Domain.

After installing this new glibc  , no performance improvement.  BUT  an strace
on openldap shows nanosleep calls very long to return (before and after this new
librarie, and with/without tls) .  I think this is an explanation about long
response and cpus inactivities if openldap spend all its time inside
nanosleep().

Do you know a workaround  on a xen 3.0.1. I can compile almost everythink now. 
XenU kernels, glibc libraries or openldap sources. I am a intensive Sun jvm user
, for this soft I can''t modify jvm code if a nanosleep() function is
called ...

Alexandre LABICHE 

From: "LABICHE Alexandre" 
To: per.buer@linpro.no
CC: xen-users@lists.xensource.com
Subject: Re: [Xen-users] Poor performance with openldap 2.3.x (Berkeley DB 4.3or
4.4) on XEN 3.0.x
Date: Sun, 05 Feb 2006 16:34:14 +0000

Hi Per ,

Yes I have disabled TLS and there ''is no performance improvement. I am
on RHEL 4 Update 2 (great stability , on my opinion , far better than RHEL3 on
SMP computers ...)

and I don''t know exactly how to obtain a Xen-friendly glibc.  Sure
!!! it should be interesting to do this, because of the 30 times less
performance on openldap .

Alexandre LABICHE 

From: Per Andreas Buer 
To: LABICHE Alexandre 
CC: xen-users@lists.xensource.com
Subject: Re: [Xen-users] Poor performance with openldap 2.3.x (Berkeley DB 4.3
or 4.4) on XEN 3.0.x
Date: Sat, 04 Feb 2006 12:05:30 +0100
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
>Hi Alexandre,
>
>Have you disabled TLS or installed a Xen-friendly glibc? TLS will
>cause performance problems om i686 unless disabled.
>
>
>LABICHE Alexandre wrote:
> >
> > Dear all,
> >
> > With or without /lib/tls librairies activated, A search in
openldap
> > is very slow on XEN 3.0.x . Cpus do nothing .
> >
> > 15000 entries are dumped in 2 minutes whereas same search
without
> > 
xen are dumped in 4 seconds (with far more activitie on CPUs)
> >
> > I have already see one or mail about this problem . But I
don''t
> > see a solution , perhaps a threading problem between Berkeley
DB
> > and XEN ?
> >
> > Versions used.
> >
> > (Openldap 2.3.x)
> >
> > (Berkeley DB 4.3 or 4.4)
> >
> > Alexandre LABICHE
> >
> >
----------------------------------------------------------------------
> >
> >
> > _______________________________________________ Xen-users
mailing
> > list Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
>
>
>- --
>Per Andreas Buer
>Linpro AS / Ledende på Linux i Norge
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>Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
>
>iD8DBQFD5Ip6puKOrqisFwERAnmYAJ97L0qMMymTxH79u6UhAg3R6Uw7gACfdk6c
>xs5M8+McszAXTK1m3b7bJv4>=nEqo
>-----END PGP SIGNATURE-----
>

>_______________________________________________
>Xen-users mailing list
>Xen-users@lists.xensource.com
>http://lists.xensource.com/xen-users

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