Re: [Xen-users] Poor performance with openldap 2.3.x (Berkeley DB 4.3or 4.4) on XEN 3.0

["LABICHE Alexandre" <alexandrelabiche@xxxxxxxxxxx>]

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" <alexandrelabiche@xxxxxxxxxxx>
To: per.buer@xxxxxxxxx
CC: xen-users@xxxxxxxxxxxxxxxxxxx
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 <per.buer@xxxxxxxxx>
To: LABICHE Alexandre <alexandrelabiche@xxxxxxxxxxx>
CC: xen-users@xxxxxxxxxxxxxxxxxxx
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@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
>
>
>- --
>Per Andreas Buer
>Linpro AS / Ledende på Linux i Norge
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