High CPU utilization on RHEL5.6/CentOS5.6

I have a MJPEG streaming system which uses mod_perl in the web
interface to supply the final stream to the client.

I am seeing high cpu utilization under RHEL5.6 which I don't see on
FC14. We are talking sub 10% on FC14 vs 80% on EL5. This is on
different hardware, but not that different. And on EL5 the httpd
session is way higher (cpu wise) than the supplying proxy. On FC14 on
my test rig I see (for a 25fps stream) 15-18% CPU for the proxy which
can handle multiplexing etc and 5.5-8% for the mod_perl httpd session.

I think this is an issue with that platform, but I haven't seen
any/many reports. Does anyone have a sec to look at the source? I
don't think I have implemented this is a horrible inefficient way but
who knows. It is true, I could have byte markers and then know the
size of the JPEG I am expecting rather than just splitting on the
boundary field, but in tests (and production) it seemed to work ok.

http://svn.codaxus.com/flexTPS/2.x.x/trunk/portal/2.4.x/site/perl/nph-mjpeg_stream.pl

Any comments or critiques would be appreciated,
Christopher

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On FC14:
Requires: httpd >= 2.2.17-1
Requires: mod_perl >= 2.0.4-11
Requires: mod_ssl >= 1:2.2.17-1
Requires: perl >= 5.12.3-141
Requires: perl-CGI >= 3.51-1
Requires: perl-Digest-SHA1 >= 2.12-4
Requires: perl-XML-Filter-BufferText >= 1.01-9
Requires: perl-XML-Simple >= 2.18-7
Requires: perl-XML-Validator-Schema >= 1.10-5
Requires: perl-Tree-DAG_Node >= 1.06-8
Requires: perl-LDAP >= 0.40-2
Requires: perl-Crypt-SSLeay >= 0.58-1
Requires: ffmpeg >= 0.6-4

On EL5:
Requires: httpd >= 2.2.3-45
Requires: mod_perl >= 2.0.4-6
Requires: mod_ssl >= 2.2.3-45
Requires: perl >= 5.8.8-32
Requires: perl-Digest-SHA1 >= 2.11-1
Requires: perl-XML-Filter-BufferText >= 1.01
Requires: perl-XML-Simple >= 2.14-4
Requires: perl-XML-Validator-Schema >= 1.10-1
Requires: perl-Tree-DAG_Node >= 1.06
Requires: perl-LDAP >= 0.33-3
Requires: perl-Crypt-SSLeay >= 0.51-11
Requires: ffmpeg >= 0.6.1-1