On Wed, 10 Jan 2007, Dave Marquardt wrote:
"Justin" == Justin Zygmont <[EMAIL PROTECTED]> writes:
Justin> On Tue, 9 Jan 2007, Darren J Moffat wrote:
Nikolay Piskun wrote:
I am trying to implement in C++ something like what I get from: kstat -m
cpu_info | grep core_id
That isn't what I was asking.
Once you know the number of cores vs threads vs sockets etc what are you
planning on doing with the information in your application ?
I very very very strongly advise against any application code making
scheduling or optimisation or scaling decisions based on this
information. I guarantee even if you get it correct now the next
processor will change things for you (no that isn't a prediction on Sun's
next hardware being different just a fact that for applications this just
isn't meaningful information).
One type of application where I think it is okay to know this information
is one giving information about the platform - for example a management
agent for SNMP or something like that.
Justin> does anyone know of any resources that explains about how
Justin> these T1 cpu's operate in everyday use. I think many people
Justin> may not fully understand how the threading can be an advantage
Justin> or how to make better use of it.
Or worse, they *think* they understand it, then try running a workload
that can't take advantage of it and complain about the poor
performance.
One place to start:
http://www.sun.com/servers/coolthreads/overview/cooltools.jsp
Additionally, potential customers might (probably) want to run cooltst
<URL:http://cooltools.sunsource.net/cooltst/> to see if their
application is suitable for use with a T1000 or T2000.
Is that what you're looking for, or more technical details about how a
T1 processor works w.r.t. how threads are scheduled, how cores are
shared between threads, etc.?
thanks, I guess theres more and more stuff for the T1's coming out all the
time. In my case I used a T2000 with Oracle 9, and was disappointed with
the performance. I see most of the time psrstat only shows 1 thread is
used 100% while the others have only light usage, and corestat rarely
shows more than 25% load in the first core, and less in the others. I
know Oracle is a typical multithreadded program, just how you're supposed
to make use of it i'm not so clear on. I think more examples and
explanation of different threading senarios would help. for example, if I
had a shell script that had to gzip 20 files, what would be the right way, fork
out 20 instances to gzip from a loop, recompile gzip to use threads?, and
what part the OS would do. Nothing i've ever read would say that a
process is limited to 6.25% of the CPU usage for a 4 core T1 (100 / 16)
thats what top shows.
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