Hello list, This is my first attempt at running Xen, and so far it has been incredible. However, I don''t think it''s going to work for the specific application I was trying to use it for. We have a web management system which uses a MySQL backend. We have put the MySQL server on a dual cpu motherboard with 2 dual-core XEON''s with hyperthreading. I noticed that MySQL would only run on one core with a total CPU usage of 25% (due to performance issues I had disabled hyperthreading). While searching forums and such about MySQL threading a few people had mentioned going VMWARE because MySQL did not support threading natively. However I am a big fan open source and I like that Xen was not a userspace virtualization so I gave it a try. I''ve been running into the same problem with Xen. I cannot get it to use more than one core with MySQL. What I am looking to do is have the DomU have one vcpu and have Xen thread it''s vcpu across all 8 physical cpus. I am naive in thinking this is possible with any virtualization? When doing my research the User Manual seems to say that this is possible: " Xen allows a domain''s virtual CPU(s) to be associated with one or more host CPUs. This can be used to allocate real resources among one or more guests, or to make optimal use of processor resources when utilizing dual-core, hyperthreading, or other advanced CPU technologies." If this is possible, how would one configure it? Thank you for your time, -Shem Valentine _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Nico Kadel-Garcia
2007-Aug-21 07:21 UTC
Re: [Xen-users] Assign multiple cpu''s to a single vcpu
Shem Valentine wrote:> Hello list, > > This is my first attempt at running Xen, and so far it has been > incredible. However, I don''t think it''s going to work for the specific > application I was trying to use it for. > > We have a web management system which uses a MySQL backend. We have put > the MySQL server on a dual cpu motherboard with 2 dual-core XEON''s with > hyperthreading. I noticed that MySQL would only run on one core with a > total CPU usage of 25% (due to performance issues I had disabled > hyperthreading). While searching forums and such about MySQL threading > a few people had mentioned going VMWARE because MySQL did not support > threading natively. However I am a big fan open source and I like that > Xen was not a userspace virtualization so I gave it a try. > > I''ve been running into the same problem with Xen. I cannot get it to > use more than one core with MySQL. What I am looking to do is have the > DomU have one vcpu and have Xen thread it''s vcpu across all 8 physical > cpus. I am naive in thinking this is possible with any virtualization? > > When doing my research the User Manual seems to say that this is possible: > " Xen allows a domain''s virtual CPU(s) to be associated with one or more > host CPUs. This can be used to allocate real resources among one or more > guests, or to make optimal use of processor resources when utilizing > dual-core, hyperthreading, or other advanced CPU technologies." >Which version of Xen? And what do your guest domain configurtions look like?There are certainly options in the config files to enable this. And what does /proc/cpuinfo say on your Dom0? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Artur Linhart - Linux communication
2007-Aug-27 20:22 UTC
RE: [Xen-users] Assign multiple cpu''s to a single vcpu
Hello, There are following options as far as I know - but You maybe know it already, it is commonly known: A. Flag vcpus: vcpus=N # N .. number of virtual processors B. flag cpus: #cpus = "" # leave to Xen to pick #cpus = "0" # all vcpus run on CPU0 #cpus = "0-3,5,^1" # run on cpus 0,2,3,5 I have installed in the last week two DomUs with the MySQL for tests, so maybe I could test Your problems on my instances if I can reproduce the problems - but I am not very skilled in MySQL, so can you help me - how did You figure out the MySQL daemon is not using more than 1 vcpu? The only statement/diagnostics inside of MySQL which I found is something like show engine InnoDB status; But there is written nothing about the CPUs... I do not think one thread could run on more CPUs - but at least there are more threads running if You run MySQL... I do not understand what does it mean if You write " MySQL did not support threading natively "... As far as I know, nearly every DBMS supports the processing of the requests (at least from multiple clients) in multiple threads - if all clients would run only in 1 thread, the performance would be very very poor... The poor performance of the DB can also be connected with the fact You use the DOmU installed in a file, not on the block device, what causes a common performance problems in the case of heavy R/W disk operations - what can be the problem i the case of DB management systems. What MySQL Version do You use? With best regards Archie -----Original Message----- From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Shem Valentine Sent: Tuesday, August 21, 2007 9:17 AM To: xen-users@lists.xensource.com Subject: [Xen-users] Assign multiple cpu''s to a single vcpu Hello list, This is my first attempt at running Xen, and so far it has been incredible. However, I don''t think it''s going to work for the specific application I was trying to use it for. We have a web management system which uses a MySQL backend. We have put the MySQL server on a dual cpu motherboard with 2 dual-core XEON''s with hyperthreading. I noticed that MySQL would only run on one core with a total CPU usage of 25% (due to performance issues I had disabled hyperthreading). While searching forums and such about MySQL threading a few people had mentioned going VMWARE because MySQL did not support threading natively. However I am a big fan open source and I like that Xen was not a userspace virtualization so I gave it a try. I''ve been running into the same problem with Xen. I cannot get it to use more than one core with MySQL. What I am looking to do is have the DomU have one vcpu and have Xen thread it''s vcpu across all 8 physical cpus. I am naive in thinking this is possible with any virtualization? When doing my research the User Manual seems to say that this is possible: " Xen allows a domain''s virtual CPU(s) to be associated with one or more host CPUs. This can be used to allocate real resources among one or more guests, or to make optimal use of processor resources when utilizing dual-core, hyperthreading, or other advanced CPU technologies." If this is possible, how would one configure it? Thank you for your time, -Shem Valentine _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users __________ Informace od NOD32 2472 (20070821) __________ Tato zprava byla proverena antivirovym systemem NOD32. http://www.nod32.cz _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users