Hi all:
I am a newbie, and i am employing KERNPROF to evaluate
something, but a problem is obsessing me.
when i tried to run it on a 2-way Xeon machine, some
troubles occurred.
In time domain it has no any problem, but in PMC domain kernprof
reports as follows:
kernel does not support PMC domain.
My kernel is 2.4.20.
i found there are several lines in smpboot.c:
#if defined(CONFIG_KERNPROF)
/*
* Set up all local APIC performance counter overflow vectors,
* if available:
*/
if (cpu_has_msr && boot_cpu_data.x86 == 6)
setup_APIC_perfctr();
#endif
but my system reported CPU family is 15, that's say,
boot_cpu_data.x86 !=6, so i think this maybe lead to problem.
In another file: drivers/char/kernprof.c,
case PROF_SET_DOMAIN:
if (arg != prof_domain) /* changing domains stops profiling
*/
prof_stop();
if (arg == PROF_DOMAIN_TIME) {
prof_domain = arg;
prof_intr_hook = &prof_timer_hook;
} else if (arg == PROF_DOMAIN_PERFCTR && have_perfctr()) {
~~~~~~~~~~~~~~~
prof_domain = arg;
prof_intr_hook = &prof_perfctr_aux_hook;
} else
err = -EINVAL;
break;
have_perfctr() return 0,
i found have_perfctr() in include/asm/kernprof.h:
#ifdef CONFIG_X86_LOCAL_APIC
#define have_perfctr() (cpu_has_msr && boot_cpu_data.x86 == 6)
...
i modified include/asm/kernprof.h to:
#define have_perfctr() (cpu_has_msr && boot_cpu_data.x86 >= 6)
and modified smpboot.c as follows:
if (cpu_has_msr && boot_cpu_data.x86 >= 6)
setup_APIC_perfctr();
then compiled kernel and rebooted with new kernel,
this time, when running kernprof with "-d pmc", kernel panic.
who can give me some advices?
any comments are welcome.
Best regards.
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