Hello Stephane, While trying to test my implementation of resend_irq for POWER, I ran into a perfmon2 problem, I think.
In order to increase the number of PMU interrupts I'm getting, I decided to start with a PAPI C test case "first.c" and modify it so that it records both user and kernel domain, and adds a call to PAPI_overflow to set the threshold on PAPI_TOT_CYC to 1 million so that I'd get about 2000 PMU interrupts per second (2 GHz processor) just as a starting point. The overflow handler passed to PAPI_overflow() does nothing other than print a count of overflows received every 1000 counts. Well, I can run this test case to completion sometimes, but fairly often it will hang in the kernel with a stack trace similar to this: 3:mon> c0 0:mon> t [c00000002e32eef0] c0000000004b18d4 ._spin_lock+0x5c/0x88 [c00000002e32ef70] c00000000004991c .task_rq_lock+0x68/0xcc [c00000002e32f010] c000000000049b48 .try_to_wake_up+0x40/0x1c0 [c00000002e32f0d0] c000000000062758 .signal_wake_up+0x48/0x74 [c00000002e32f160] c000000000062a88 .__group_send_sig_info+0xa8/0xcc [c00000002e32f200] c0000000000631fc .group_send_sig_info+0x64/0xa0 [c00000002e32f2b0] c0000000000eca24 .send_sigio+0x124/0x1f0 [c00000002e32f3f0] c0000000000ecb5c .__kill_fasync+0x6c/0xa0 [c00000002e32f480] c0000000000ecbec .kill_fasync+0x5c/0x94 [c00000002e32f520] c00000000024d6c4 .pfm_notify_user+0xd4/0xf0 [c00000002e32f5a0] c00000000024d850 .pfm_ovfl_notify+0x170/0x198 [c00000002e32f640] c00000000024b314 .pfm_interrupt_handler+0xbec/0xf9c [c00000002e32f7b0] d0000000000e82f4 .pfm_power5_irq_handler+0x40/0x80 [perfmon_power5] [c00000002e32f840] c000000000043dbc .powerpc_irq_handler+0x60/0x78 [c00000002e32f8c0] c000000000023488 .performance_monitor_exception+0x38/0x50 [c00000002e32f940] c000000000003d80 performance_monitor_common+0x100/0x180 --- Exception: f00 (Performance Monitor) at c000000000045e38 .__enqueue_entity+0 x3c/0xb8 [c00000002e32fcb0] c00000000004e5e8 .put_prev_task_fair+0x74/0x98 [c00000002e32fd40] c0000000004af708 .schedule+0x46c/0x768 [c00000002e32fe30] c000000000008c54 do_work+0x14/0x34 --- Exception: 901 (Decrementer) at 0000000010001ff8 SP (ffffd320) is in userspace So what we have here is that spin_lock is getting called in the context of schedule(). That doesn't seem good to me, but I'm am not wise enough in the ways of the Linux kernel. Do you think this should work correctly? To make forward progress on resend_irq, I'm going to switch away from using an overflow handler to a sampler test case, so this shouldn't stop my progress, it will just slow me down a bit. Regards, - Corey -- Corey Ashford Software Engineer IBM Linux Technology Center, Linux Toolchain Beaverton, OR 503-578-3507 [EMAIL PROTECTED] ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ perfmon2-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
