Am Samstag, den 27.01.2007, 00:15 -0700 schrieb Bernard Johnson: > Nils Toedtmann wrote: > > I guess they did not disappear but got hidden. AFAIK (correct me if i am > > wrong) recent xen versions have a hack to workaround TLS-libs silently, > > but there is still a performance penalty. > > That was not my understanding, however you may be right. Can you point > me to documentation as to what the workaround actually does? And what > performance penalty we might be paying? Am Sonntag, den 28.01.2007, 18:45 +0000 schrieb Karanbir Singh: > Do you have some numbers to elaborate on the point of performance loss ? OK, i digged the MLs ... If there are Xen-incompatible NPTL/TLS libs, then Xen3 does a "TLS emulation" which gives threaded apps a performance penalty, at least on i86_32 systems (i am not sure about i86_64): <http://wiki.xensource.com/xenwiki/XenFaq> (item 4.1) <http://wiki.xensource.com/xenwiki/XenSpecificGlibc> <http://lists.xensource.com/archives/cgi-bin/namazu.cgi?query=%22tls +emulation%22&submit=Search&idxname=xen-users> This mail <http://lists.xensource.com/archives/html/xen-users/2007-01/msg00913.html> from Xen developer Keir Fraser is 9 days old and references to Xen 3.0.4 (which unfortunatly _needs_ TLS in Dom0 for xen-libs): "For now you can simply use the /lib/tls libraries — you’ll get a warning during boot and performance in domain0 will be reduced" >From the rumors i have read on the xen MLs, OpenLDAP and java suffer from that problem heavily, but i did not find benchmarks comparing xen-compatible vs. xen-emulated TLS. Sorry, that is all i can tell on that topic, i'm just another admin reading MLs... /nils.