Hello all, I can't get my athlon x2 processor working at 100% on cpu-intensive apps. I've made some tests with "john --test" and "transcode", wich are both multithreaded apps. For example if I launch transcode it takes between 50% and 55% cpu (on top), and if I launch a second transcode session on another file, the total cpu used on top is 100%, without lower the speed of the first transcode session. The same behavior occurs with john. A single "john --test" give me some speed results, and the same command with a transcode or second "john --test" give me the same speed results but now with 100% cpu used. I made a "portupgrade -auf" just after building and installing my SMP kernel and World, to be sure all is up-to-date. So it's seems it's not a "top" output problem, but a real underuse of the computing power. %uname -a FreeBSD wks02.chez.oim 6.1-STABLE FreeBSD 6.1-STABLE #0: Thu Aug 17 18:47:31 CEST 2006 laurent@wks02.chez.oim:/usr/obj/usr/src/sys/WKS02_SMP amd64 Does anyone could explain me what's happening with my system ? -- Laurent C.
On Thursday 24 August 2006 13:09, Laurent C wrote:> Hello all, > > I can't get my athlon x2 processor working at 100% on cpu-intensive > apps. I've made some tests with "john --test" and "transcode", wich > are both multithreaded apps. > > For example if I launch transcode it takes between 50% and 55% cpu > (on top), and if I launch > a second transcode session on another file, the total cpu used on > top is 100%, without lower the speed > of the first transcode session. > > The same behavior occurs with john. A single "john --test" give me > some speed results, and the same > command with a transcode or second "john --test" give me the same > speed results but now with 100% > cpu used. > > I made a "portupgrade -auf" just after building and installing my > SMP kernel and World, to be sure all is up-to-date. > > So it's seems it's not a "top" output problem, but a real underuse > of the computing power. > > %uname -a > FreeBSD wks02.chez.oim 6.1-STABLE FreeBSD 6.1-STABLE #0: Thu Aug 17 > 18:47:31 CEST 2006 > laurent@wks02.chez.oim:/usr/obj/usr/src/sys/WKS02_SMP amd64 > > Does anyone could explain me what's happening with my system ?An application that is not written to take advantage of a multi-cpu system is unable to max out more than one CPU at a time. top isn't really SMP 'aware' so in a dual CPU system something that is using 50% of the CPU is in reality maxing one CPU. This is a bit over-simplified because the process will bounce between the two CPUs but it will never execute on more than one at a time. -- Thanks, Josh Paetzel
On Thu, Aug 24, 2006 at 08:09:35PM +0200, Laurent C wrote:> Hello all, > > I can't get my athlon x2 processor working at 100% on cpu-intensive apps. > I've made some tests with "john --test" and "transcode", wich are both > multithreaded apps. > > For example if I launch transcode it takes between 50% and 55% cpu (on top), > and if I launch > a second transcode session on another file, the total cpu used on top is > 100%, without lower the speed > of the first transcode session. > > The same behavior occurs with john. A single "john --test" give me some > speed results, and the same > command with a transcode or second "john --test" give me the same speed > results but now with 100% > cpu used. > > I made a "portupgrade -auf" just after building and installing my SMP kernel > and World, to be sure all is up-to-date. > > So it's seems it's not a "top" output problem, but a real underuse of the > computing power. > > %uname -a > FreeBSD wks02.chez.oim 6.1-STABLE FreeBSD 6.1-STABLE #0: Thu Aug 17 18:47:31 > CEST 2006 laurent@wks02.chez.oim:/usr/obj/usr/src/sys/WKS02_SMP amd64 > > Does anyone could explain me what's happening with my system ?How do you know the applications are running with two threads? Presumably you need to specify the amount of parallelism. Kris -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 187 bytes Desc: not available Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20060824/7cd2dde3/attachment.pgp