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Commit 159a80b2 authored by Robert Richter's avatar Robert Richter
Browse files

oprofile, x86: Add kernel parameter oprofile.cpu_type=timer 



We need this to better test x86 NMI timer mode. Otherwise it is very
hard to setup systems with NMI timer enabled, but we have this e.g. in
virtual machine environments.

Signed-off-by: default avatarRobert Richter <robert.richter@amd.com>
parent 97f7f818

Documentation/kernel-parameters.txt

+3 −0
Original line number Diff line number Diff line
@@ -1848,6 +1848,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			arch_perfmon: [X86] Force use of architectural

				perfmon on Intel CPUs instead of the

				CPU specific event set.

			timer: [X86] Force use of architectural NMI

				timer mode (see also oprofile.timer

				for generic hr timer mode)



	oops=panic	Always panic on oopses. Default is to just kill the

			process, but there is a small probability of

arch/x86/oprofile/nmi_int.c

+21 −6
Original line number Diff line number Diff line
@@ -613,24 +613,36 @@ static int __init p4_init(char **cpu_type) 
	return 0;

}



static int force_arch_perfmon;

static int force_cpu_type(const char *str, struct kernel_param *kp)

enum __force_cpu_type {

	reserved = 0,		/* do not force */

	timer,

	arch_perfmon,

};



static int force_cpu_type;



static int set_cpu_type(const char *str, struct kernel_param *kp)

{

	if (!strcmp(str, "arch_perfmon")) {

		force_arch_perfmon = 1;

	if (!strcmp(str, "timer")) {

		force_cpu_type = timer;

		printk(KERN_INFO "oprofile: forcing NMI timer mode\n");

	} else if (!strcmp(str, "arch_perfmon")) {

		force_cpu_type = arch_perfmon;

		printk(KERN_INFO "oprofile: forcing architectural perfmon\n");

	} else {

		force_cpu_type = 0;

	}



	return 0;

}

module_param_call(cpu_type, force_cpu_type, NULL, NULL, 0);

module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);



static int __init ppro_init(char **cpu_type)

{

	__u8 cpu_model = boot_cpu_data.x86_model;

	struct op_x86_model_spec *spec = &op_ppro_spec;	/* default */



	if (force_arch_perfmon && cpu_has_arch_perfmon)

	if (force_cpu_type == arch_perfmon && cpu_has_arch_perfmon)

		return 0;



	/*
@@ -697,6 +709,9 @@ int __init op_nmi_init(struct oprofile_operations *ops) 
	if (!cpu_has_apic)

		return -ENODEV;



	if (force_cpu_type == timer)

		return -ENODEV;



	switch (vendor) {

	case X86_VENDOR_AMD:

		/* Needs to be at least an Athlon (or hammer in 32bit mode) */