Messages in this thread Patch in this message | | | Subject | [RFC][PATCH] dynamically enable readprofile at runtime | From | Dave Hansen <> | Date | Fri, 29 Aug 2008 13:27:13 -0700 |
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Way too often, I have a machine that exhibits some kind of crappy behavior. The CPU looks wedged in the kernel or it is spending way too much system time and I wonder what is responsible.
I try to run readprofile. But, of course, Ubuntu doesn't enable it by default. Dang!
The reason we boot-time enable it is that it takes a big bufffer that we generally can only bootmem alloc. But, does it hurt to at least try and runtime-alloc it?
To use: echo 2 > /sys/kernel/profile
Then run readprofile like normal.
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> ---
linux-2.6.git-dave/kernel/ksysfs.c | 29 +++++++++++++++++++++++++++++ linux-2.6.git-dave/kernel/profile.c | 33 ++++++++++++++++++++++++--------- 2 files changed, 53 insertions(+), 9 deletions(-)
diff -puN kernel/ksysfs.c~dynamic-readprofile kernel/ksysfs.c --- linux-2.6.git/kernel/ksysfs.c~dynamic-readprofile 2008-08-29 13:15:52.000000000 -0700 +++ linux-2.6.git-dave/kernel/ksysfs.c 2008-08-29 13:19:03.000000000 -0700 @@ -14,6 +14,7 @@ #include <linux/module.h> #include <linux/init.h> #include <linux/kexec.h> +#include <linux/profile.h> #include <linux/sched.h> #define KERNEL_ATTR_RO(_name) \ @@ -53,6 +54,31 @@ static ssize_t uevent_helper_store(struc KERNEL_ATTR_RW(uevent_helper); #endif +#ifdef CONFIG_PROFILING +/* uevent helper program, used during early boo */ +static ssize_t profiling_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", prof_on); +} +static ssize_t profiling_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int ret; + + profile_setup(buf); + profile_init(); + if (!prof_buffer) + return -ENOMEM; + ret = create_proc_profile(); + if (ret) + return ret; + return count; +} +KERNEL_ATTR_RW(profiling); +#endif + #ifdef CONFIG_KEXEC static ssize_t kexec_loaded_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) @@ -109,6 +135,9 @@ static struct attribute * kernel_attrs[] &uevent_seqnum_attr.attr, &uevent_helper_attr.attr, #endif +#ifdef CONFIG_PROFILING + &profiling_attr.attr, +#endif #ifdef CONFIG_KEXEC &kexec_loaded_attr.attr, &kexec_crash_loaded_attr.attr, diff -puN kernel/profile.c~dynamic-readprofile kernel/profile.c --- linux-2.6.git/kernel/profile.c~dynamic-readprofile 2008-08-29 13:15:52.000000000 -0700 +++ linux-2.6.git-dave/kernel/profile.c 2008-08-29 13:18:50.000000000 -0700 @@ -50,11 +50,11 @@ static DEFINE_PER_CPU(int, cpu_profile_f static DEFINE_MUTEX(profile_flip_mutex); #endif /* CONFIG_SMP */ -static int __init profile_setup(char *str) +int profile_setup(char *str) { - static char __initdata schedstr[] = "schedule"; - static char __initdata sleepstr[] = "sleep"; - static char __initdata kvmstr[] = "kvm"; + static char schedstr[] = "schedule"; + static char sleepstr[] = "sleep"; + static char kvmstr[] = "kvm"; int par; if (!strncmp(str, sleepstr, strlen(sleepstr))) { @@ -100,14 +100,29 @@ static int __init profile_setup(char *st __setup("profile=", profile_setup); -void __init profile_init(void) +void profile_init(void) { + int buffer_bytes; if (!prof_on) return; /* only text is profiled */ prof_len = (_etext - _stext) >> prof_shift; - prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t)); + buffer_bytes = prof_len*sizeof(atomic_t); + if (!slab_is_available()) { + prof_buffer = alloc_bootmem(buffer_bytes); + return; + } + + prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL); + if (prof_buffer) + return; + + prof_buffer = alloc_pages_exact(buffer_bytes, GFP_KERNEL|__GFP_ZERO); + if (prof_buffer) + return; + + prof_buffer = vmalloc(buffer_bytes); } /* Profile event notifications */ @@ -527,7 +542,7 @@ static void __init profile_nop(void *unu { } -static int __init create_hash_tables(void) +static int create_hash_tables(void) { int cpu; @@ -575,14 +590,14 @@ out_cleanup: #define create_hash_tables() ({ 0; }) #endif -static int __init create_proc_profile(void) +int create_proc_profile(void) { struct proc_dir_entry *entry; if (!prof_on) return 0; if (create_hash_tables()) - return -1; + return -ENOMEM; entry = proc_create("profile", S_IWUSR | S_IRUGO, NULL, &proc_profile_operations); if (!entry) _
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