Messages in this thread | | | Date | Sat, 20 Jan 2007 02:18:45 +0100 | From | "J.A. Magallón" <> | Subject | Re: Threading... |
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On Fri, 19 Jan 2007 19:55:41 +0100, Arjan van de Ven <arjan@infradead.org> wrote:
> On Fri, 2007-01-19 at 10:43 -0800, Brian McGrew wrote: > > I have a very interesting question about something that we're seeing > > happening with threading between Fedora Core 3 and Fedora Core 5. Running > > on Dell PowerEdge 1800 Hardware with a Xeon processor with hyper-threading > > turned on. Both systems are using a 2.6.16.16 kernel (MVP al la special). > > > > We have a multithreaded application that starts two worker threads. On > > Fedora Core 3 both of these we use getpid() to get the PID of the thread and > > then use set_afinity to assign each thread to it's own CPU. Both threads > > run almost symmetrically even on their given CPU watching the system > > monitor. > > this is odd; even in FC3 getpid() is supposed to return the process ID > not the thread ID > > > What am I missing? What do I need to do in FC5 or the kernel or the > > threading library to get my threads to run in symmetric parallel again??? >
One thing to try. In linux, pthread_setconcurrency never did nothing (it _really_ did in IRIX...). Can you try that ? Perhaps FC5 has implemented some kind of scheduling policy like that on irix (everything stays on the same CPU until it starts to suck cycles, unless you use setconcurrency).
-- J.A. Magallon <jamagallon()ono!com> \ Software is like sex: \ It's better when it's free Mandriva Linux release 2007.1 (Cooker) for i586 Linux 2.6.19-jam04 (gcc 4.1.2 20061110 (prerelease) (4.1.2-0.20061110.2mdv2007.1)) #0 SMP PREEMPT - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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