John, On PIII, CPU_CLK_UNHALTED is broken and keeps on counting while in HALT state. On Fri, Jul 13, 2007 at 02:33:09PM +0200, John Sigler wrote: > [ Note: cross-posted to linux-rt-users and oprofile-list ] > > Hello, > > The x86 Performance Monitoring Event "CPU_CLK_UNHALTED" is defined as: > Number of cycles during which the processor is not halted. > > IIUC, when the CPU is in the HALT state, CPU_CLK_UNHALTED should not > increment, right? When Linux has nothing to do, it executes HLT. > > http://lxr.linux.no/source/arch/i386/kernel/process.c#L101 > > I set up OProfile to sample EIP every 200000 CPU_CLK_UNHALTED cycles on > an idle system. I was expecting a very small number of samples, since > CPU_CLK_UNHALTED should not increment (most of the time). > > I ran the daemon 5 minutes on a idle system > > # opreport -l > CPU: PIII, speed 1266.7 MHz (estimated) > Counted CPU_CLK_UNHALTED events (clocks processor is not halted) with a > unit mask of 0x00 (No unit mask) count 200000 > samples % symbol name > 1868484 99.4914 cpu_idle > 4560 0.2428 (oprofiled) > 727 0.0387 ip_route_input > 457 0.0243 acpi_ev_asynch_execute_gpe_method > 454 0.0242 ip_route_output_slow > 286 0.0152 dma_free_coherent > 280 0.0149 ip_route_input_slow > 273 0.0145 acpi_ex_opcode_6A_0T_1R > 220 0.0117 __acpi_nmi_disable > 130 0.0069 Dta1xxRxProcessStatusFlags > 94 0.0050 Dta1xxTxProcessStatusFlags > 93 0.0050 (bash) > 85 0.0045 Dta1xxIsr > 79 0.0042 intel_machine_check > 56 0.0030 sys_olduname > 51 0.0027 Dta1xxPeriodicIntHandler > > cpu_idle breakdown: > > c0100e70 1 5.4e-05 > c0100e71 1 5.4e-05 > c0100e78 1 5.4e-05 > c0100e88 1 5.4e-05 > c0100e8a 1 5.4e-05 > c0100e97 4 2.1e-04 > c0100ea8 1868475 99.9995 > > cpu_idle objdump: > > c0100ea6: fb sti > c0100ea7: f4 hlt > c0100ea8: eb 0b jmp c0100eb5 > > (If an interrupt is used to resume execution after a HLT instruction, > the saved instruction pointer points to the instruction following the > HLT instruction.) > > oprofiled collected 1878300 samples. In other words, the system received > 1878300 NMIs. (5 * 60 * 1.2667e9) / 1878300 = 202316 cycles between NMI > > Seems like CPU_CLK_UNHALTED increments every cycle. > > Perhaps HLT does not put my CPU in the HALT state? > > Did I miss something? > > Regards. > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > oprofile-list mailing list > oprofile-list@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/oprofile-list -- -Stephane - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
