Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core

This commit is contained in:
Ingo Molnar
2010-06-09 18:55:20 +02:00
35 changed files with 130 additions and 1309 deletions
@@ -1,71 +0,0 @@
What: /sys/kernel/debug/kmemtrace/
Date: July 2008
Contact: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Description:
In kmemtrace-enabled kernels, the following files are created:
/sys/kernel/debug/kmemtrace/
cpu<n> (0400) Per-CPU tracing data, see below. (binary)
total_overruns (0400) Total number of bytes which were dropped from
cpu<n> files because of full buffer condition,
non-binary. (text)
abi_version (0400) Kernel's kmemtrace ABI version. (text)
Each per-CPU file should be read according to the relay interface. That is,
the reader should set affinity to that specific CPU and, as currently done by
the userspace application (though there are other methods), use poll() with
an infinite timeout before every read(). Otherwise, erroneous data may be
read. The binary data has the following _core_ format:
Event ID (1 byte) Unsigned integer, one of:
0 - represents an allocation (KMEMTRACE_EVENT_ALLOC)
1 - represents a freeing of previously allocated memory
(KMEMTRACE_EVENT_FREE)
Type ID (1 byte) Unsigned integer, one of:
0 - this is a kmalloc() / kfree()
1 - this is a kmem_cache_alloc() / kmem_cache_free()
2 - this is a __get_free_pages() et al.
Event size (2 bytes) Unsigned integer representing the
size of this event. Used to extend
kmemtrace. Discard the bytes you
don't know about.
Sequence number (4 bytes) Signed integer used to reorder data
logged on SMP machines. Wraparound
must be taken into account, although
it is unlikely.
Caller address (8 bytes) Return address to the caller.
Pointer to mem (8 bytes) Pointer to target memory area. Can be
NULL, but not all such calls might be
recorded.
In case of KMEMTRACE_EVENT_ALLOC events, the next fields follow:
Requested bytes (8 bytes) Total number of requested bytes,
unsigned, must not be zero.
Allocated bytes (8 bytes) Total number of actually allocated
bytes, unsigned, must not be lower
than requested bytes.
Requested flags (4 bytes) GFP flags supplied by the caller.
Target CPU (4 bytes) Signed integer, valid for event id 1.
If equal to -1, target CPU is the same
as origin CPU, but the reverse might
not be true.
The data is made available in the same endianness the machine has.
Other event ids and type ids may be defined and added. Other fields may be
added by increasing event size, but see below for details.
Every modification to the ABI, including new id definitions, are followed
by bumping the ABI version by one.
Adding new data to the packet (features) is done at the end of the mandatory
data:
Feature size (2 byte)
Feature ID (1 byte)
Feature data (Feature size - 3 bytes)
Users:
kmemtrace-user - git://repo.or.cz/kmemtrace-user.git
-126
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@@ -1,126 +0,0 @@
kmemtrace - Kernel Memory Tracer
by Eduard - Gabriel Munteanu
<eduard.munteanu@linux360.ro>
I. Introduction
===============
kmemtrace helps kernel developers figure out two things:
1) how different allocators (SLAB, SLUB etc.) perform
2) how kernel code allocates memory and how much
To do this, we trace every allocation and export information to the userspace
through the relay interface. We export things such as the number of requested
bytes, the number of bytes actually allocated (i.e. including internal
fragmentation), whether this is a slab allocation or a plain kmalloc() and so
on.
The actual analysis is performed by a userspace tool (see section III for
details on where to get it from). It logs the data exported by the kernel,
processes it and (as of writing this) can provide the following information:
- the total amount of memory allocated and fragmentation per call-site
- the amount of memory allocated and fragmentation per allocation
- total memory allocated and fragmentation in the collected dataset
- number of cross-CPU allocation and frees (makes sense in NUMA environments)
Moreover, it can potentially find inconsistent and erroneous behavior in
kernel code, such as using slab free functions on kmalloc'ed memory or
allocating less memory than requested (but not truly failed allocations).
kmemtrace also makes provisions for tracing on some arch and analysing the
data on another.
II. Design and goals
====================
kmemtrace was designed to handle rather large amounts of data. Thus, it uses
the relay interface to export whatever is logged to userspace, which then
stores it. Analysis and reporting is done asynchronously, that is, after the
data is collected and stored. By design, it allows one to log and analyse
on different machines and different arches.
As of writing this, the ABI is not considered stable, though it might not
change much. However, no guarantees are made about compatibility yet. When
deemed stable, the ABI should still allow easy extension while maintaining
backward compatibility. This is described further in Documentation/ABI.
Summary of design goals:
- allow logging and analysis to be done across different machines
- be fast and anticipate usage in high-load environments (*)
- be reasonably extensible
- make it possible for GNU/Linux distributions to have kmemtrace
included in their repositories
(*) - one of the reasons Pekka Enberg's original userspace data analysis
tool's code was rewritten from Perl to C (although this is more than a
simple conversion)
III. Quick usage guide
======================
1) Get a kernel that supports kmemtrace and build it accordingly (i.e. enable
CONFIG_KMEMTRACE).
2) Get the userspace tool and build it:
$ git clone git://repo.or.cz/kmemtrace-user.git # current repository
$ cd kmemtrace-user/
$ ./autogen.sh
$ ./configure
$ make
3) Boot the kmemtrace-enabled kernel if you haven't, preferably in the
'single' runlevel (so that relay buffers don't fill up easily), and run
kmemtrace:
# '$' does not mean user, but root here.
$ mount -t debugfs none /sys/kernel/debug
$ mount -t proc none /proc
$ cd path/to/kmemtrace-user/
$ ./kmemtraced
Wait a bit, then stop it with CTRL+C.
$ cat /sys/kernel/debug/kmemtrace/total_overruns # Check if we didn't
# overrun, should
# be zero.
$ (Optionally) [Run kmemtrace_check separately on each cpu[0-9]*.out file to
check its correctness]
$ ./kmemtrace-report
Now you should have a nice and short summary of how the allocator performs.
IV. FAQ and known issues
========================
Q: 'cat /sys/kernel/debug/kmemtrace/total_overruns' is non-zero, how do I fix
this? Should I worry?
A: If it's non-zero, this affects kmemtrace's accuracy, depending on how
large the number is. You can fix it by supplying a higher
'kmemtrace.subbufs=N' kernel parameter.
---
Q: kmemtrace_check reports errors, how do I fix this? Should I worry?
A: This is a bug and should be reported. It can occur for a variety of
reasons:
- possible bugs in relay code
- possible misuse of relay by kmemtrace
- timestamps being collected unorderly
Or you may fix it yourself and send us a patch.
---
Q: kmemtrace_report shows many errors, how do I fix this? Should I worry?
A: This is a known issue and I'm working on it. These might be true errors
in kernel code, which may have inconsistent behavior (e.g. allocating memory
with kmem_cache_alloc() and freeing it with kfree()). Pekka Enberg pointed
out this behavior may work with SLAB, but may fail with other allocators.
It may also be due to lack of tracing in some unusual allocator functions.
We don't want bug reports regarding this issue yet.
---
V. See also
===========
Documentation/kernel-parameters.txt
Documentation/ABI/testing/debugfs-kmemtrace
-7
View File
@@ -3368,13 +3368,6 @@ F: include/linux/kmemleak.h
F: mm/kmemleak.c
F: mm/kmemleak-test.c
KMEMTRACE
M: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
S: Maintained
F: Documentation/trace/kmemtrace.txt
F: include/linux/kmemtrace.h
F: kernel/trace/kmemtrace.c
KPROBES
M: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
M: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
+12
View File
@@ -21,3 +21,15 @@
#ifdef CONFIG_FSL_EMB_PERF_EVENT
#include <asm/perf_event_fsl_emb.h>
#endif
#ifdef CONFIG_PERF_EVENTS
#include <asm/ptrace.h>
#include <asm/reg.h>
#define perf_arch_fetch_caller_regs(regs, __ip) \
do { \
(regs)->nip = __ip; \
(regs)->gpr[1] = *(unsigned long *)__get_SP(); \
asm volatile("mfmsr %0" : "=r" ((regs)->msr)); \
} while (0)
#endif
-26
View File
@@ -127,29 +127,3 @@ _GLOBAL(__setup_cpu_power7)
_GLOBAL(__restore_cpu_power7)
/* place holder */
blr
/*
* Get a minimal set of registers for our caller's nth caller.
* r3 = regs pointer, r5 = n.
*
* We only get R1 (stack pointer), NIP (next instruction pointer)
* and LR (link register). These are all we can get in the
* general case without doing complicated stack unwinding, but
* fortunately they are enough to do a stack backtrace, which
* is all we need them for.
*/
_GLOBAL(perf_arch_fetch_caller_regs)
mr r6,r1
cmpwi r5,0
mflr r4
ble 2f
mtctr r5
1: PPC_LL r6,0(r6)
bdnz 1b
PPC_LL r4,PPC_LR_STKOFF(r6)
2: PPC_LL r7,0(r6)
PPC_LL r7,PPC_LR_STKOFF(r7)
PPC_STL r6,GPR1-STACK_FRAME_OVERHEAD(r3)
PPC_STL r4,_NIP-STACK_FRAME_OVERHEAD(r3)
PPC_STL r7,_LINK-STACK_FRAME_OVERHEAD(r3)
blr
+8
View File
@@ -6,7 +6,15 @@ extern void set_perf_event_pending(void);
#define PERF_EVENT_INDEX_OFFSET 0
#ifdef CONFIG_PERF_EVENTS
#include <asm/ptrace.h>
extern void init_hw_perf_events(void);
extern void
__perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip);
#define perf_arch_fetch_caller_regs(pt_regs, ip) \
__perf_arch_fetch_caller_regs(pt_regs, ip, 1);
#else
static inline void init_hw_perf_events(void) { }
#endif
+3 -3
View File
@@ -47,9 +47,9 @@ stack_trace_flush:
.size stack_trace_flush,.-stack_trace_flush
#ifdef CONFIG_PERF_EVENTS
.globl perf_arch_fetch_caller_regs
.type perf_arch_fetch_caller_regs,#function
perf_arch_fetch_caller_regs:
.globl __perf_arch_fetch_caller_regs
.type __perf_arch_fetch_caller_regs,#function
__perf_arch_fetch_caller_regs:
/* We always read the %pstate into %o5 since we will use
* that to construct a fake %tstate to store into the regs.
*/
+13
View File
@@ -141,6 +141,19 @@ extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
extern unsigned long perf_misc_flags(struct pt_regs *regs);
#define perf_misc_flags(regs) perf_misc_flags(regs)
#include <asm/stacktrace.h>
/*
* We abuse bit 3 from flags to pass exact information, see perf_misc_flags
* and the comment with PERF_EFLAGS_EXACT.
*/
#define perf_arch_fetch_caller_regs(regs, __ip) { \
(regs)->ip = (__ip); \
(regs)->bp = caller_frame_pointer(); \
(regs)->cs = __KERNEL_CS; \
regs->flags = 0; \
}
#else
static inline void init_hw_perf_events(void) { }
static inline void perf_events_lapic_init(void) { }
+49
View File
@@ -1,6 +1,13 @@
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
*/
#ifndef _ASM_X86_STACKTRACE_H
#define _ASM_X86_STACKTRACE_H
#include <linux/uaccess.h>
extern int kstack_depth_to_print;
struct thread_info;
@@ -42,4 +49,46 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data);
#ifdef CONFIG_X86_32
#define STACKSLOTS_PER_LINE 8
#define get_bp(bp) asm("movl %%ebp, %0" : "=r" (bp) :)
#else
#define STACKSLOTS_PER_LINE 4
#define get_bp(bp) asm("movq %%rbp, %0" : "=r" (bp) :)
#endif
extern void
show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp, char *log_lvl);
extern void
show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *sp, unsigned long bp, char *log_lvl);
extern unsigned int code_bytes;
/* The form of the top of the frame on the stack */
struct stack_frame {
struct stack_frame *next_frame;
unsigned long return_address;
};
struct stack_frame_ia32 {
u32 next_frame;
u32 return_address;
};
static inline unsigned long caller_frame_pointer(void)
{
struct stack_frame *frame;
get_bp(frame);
#ifdef CONFIG_FRAME_POINTER
frame = frame->next_frame;
#endif
return (unsigned long)frame;
}
#endif /* _ASM_X86_STACKTRACE_H */
-18
View File
@@ -1613,8 +1613,6 @@ static const struct stacktrace_ops backtrace_ops = {
.walk_stack = print_context_stack_bp,
};
#include "../dumpstack.h"
static void
perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
@@ -1736,22 +1734,6 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
return entry;
}
void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
{
regs->ip = ip;
/*
* perf_arch_fetch_caller_regs adds another call, we need to increment
* the skip level
*/
regs->bp = rewind_frame_pointer(skip + 1);
regs->cs = __KERNEL_CS;
/*
* We abuse bit 3 to pass exact information, see perf_misc_flags
* and the comment with PERF_EFLAGS_EXACT.
*/
regs->flags = 0;
}
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
unsigned long ip;
-1
View File
@@ -18,7 +18,6 @@
#include <asm/stacktrace.h>
#include "dumpstack.h"
int panic_on_unrecovered_nmi;
int panic_on_io_nmi;
-56
View File
@@ -1,56 +0,0 @@
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
*/
#ifndef DUMPSTACK_H
#define DUMPSTACK_H
#ifdef CONFIG_X86_32
#define STACKSLOTS_PER_LINE 8
#define get_bp(bp) asm("movl %%ebp, %0" : "=r" (bp) :)
#else
#define STACKSLOTS_PER_LINE 4
#define get_bp(bp) asm("movq %%rbp, %0" : "=r" (bp) :)
#endif
#include <linux/uaccess.h>
extern void
show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp, char *log_lvl);
extern void
show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *sp, unsigned long bp, char *log_lvl);
extern unsigned int code_bytes;
/* The form of the top of the frame on the stack */
struct stack_frame {
struct stack_frame *next_frame;
unsigned long return_address;
};
struct stack_frame_ia32 {
u32 next_frame;
u32 return_address;
};
static inline unsigned long rewind_frame_pointer(int n)
{
struct stack_frame *frame;
get_bp(frame);
#ifdef CONFIG_FRAME_POINTER
while (n--) {
if (probe_kernel_address(&frame->next_frame, frame))
break;
}
#endif
return (unsigned long)frame;
}
#endif /* DUMPSTACK_H */
-2
View File
@@ -16,8 +16,6 @@
#include <asm/stacktrace.h>
#include "dumpstack.h"
void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
-1
View File
@@ -16,7 +16,6 @@
#include <asm/stacktrace.h>
#include "dumpstack.h"
#define N_EXCEPTION_STACKS_END \
(N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
+16 -15
View File
@@ -23,11 +23,16 @@ static int save_stack_stack(void *data, char *name)
return 0;
}
static void save_stack_address(void *data, unsigned long addr, int reliable)
static void
__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
{
struct stack_trace *trace = data;
#ifdef CONFIG_FRAME_POINTER
if (!reliable)
return;
#endif
if (nosched && in_sched_functions(addr))
return;
if (trace->skip > 0) {
trace->skip--;
return;
@@ -36,20 +41,15 @@ static void save_stack_address(void *data, unsigned long addr, int reliable)
trace->entries[trace->nr_entries++] = addr;
}
static void save_stack_address(void *data, unsigned long addr, int reliable)
{
return __save_stack_address(data, addr, reliable, false);
}
static void
save_stack_address_nosched(void *data, unsigned long addr, int reliable)
{
struct stack_trace *trace = (struct stack_trace *)data;
if (!reliable)
return;
if (in_sched_functions(addr))
return;
if (trace->skip > 0) {
trace->skip--;
return;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = addr;
return __save_stack_address(data, addr, reliable, true);
}
static const struct stacktrace_ops save_stack_ops = {
@@ -96,12 +96,13 @@ EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
struct stack_frame {
struct stack_frame_user {
const void __user *next_fp;
unsigned long ret_addr;
};
static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
static int
copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
{
int ret;
@@ -126,7 +127,7 @@ static inline void __save_stack_trace_user(struct stack_trace *trace)
trace->entries[trace->nr_entries++] = regs->ip;
while (trace->nr_entries < trace->max_entries) {
struct stack_frame frame;
struct stack_frame_user frame;
frame.next_fp = NULL;
frame.ret_addr = 0;
-25
View File
@@ -1,25 +0,0 @@
/*
* Copyright (C) 2008 Eduard - Gabriel Munteanu
*
* This file is released under GPL version 2.
*/
#ifndef _LINUX_KMEMTRACE_H
#define _LINUX_KMEMTRACE_H
#ifdef __KERNEL__
#include <trace/events/kmem.h>
#ifdef CONFIG_KMEMTRACE
extern void kmemtrace_init(void);
#else
static inline void kmemtrace_init(void)
{
}
#endif
#endif /* __KERNEL__ */
#endif /* _LINUX_KMEMTRACE_H */
+7 -25
View File
@@ -932,8 +932,10 @@ extern atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
extern void __perf_sw_event(u32, u64, int, struct pt_regs *, u64);
extern void
perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip);
#ifndef perf_arch_fetch_caller_regs
static inline void
perf_arch_fetch_caller_regs(struct regs *regs, unsigned long ip) { }
#endif
/*
* Take a snapshot of the regs. Skip ip and frame pointer to
@@ -943,31 +945,11 @@ perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip);
* - bp for callchains
* - eflags, for future purposes, just in case
*/
static inline void perf_fetch_caller_regs(struct pt_regs *regs, int skip)
static inline void perf_fetch_caller_regs(struct pt_regs *regs)
{
unsigned long ip;
memset(regs, 0, sizeof(*regs));
switch (skip) {
case 1 :
ip = CALLER_ADDR0;
break;
case 2 :
ip = CALLER_ADDR1;
break;
case 3 :
ip = CALLER_ADDR2;
break;
case 4:
ip = CALLER_ADDR3;
break;
/* No need to support further for now */
default:
ip = 0;
}
return perf_arch_fetch_caller_regs(regs, ip, skip);
perf_arch_fetch_caller_regs(regs, CALLER_ADDR0);
}
static inline void
@@ -977,7 +959,7 @@ perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
struct pt_regs hot_regs;
if (!regs) {
perf_fetch_caller_regs(&hot_regs, 1);
perf_fetch_caller_regs(&hot_regs);
regs = &hot_regs;
}
__perf_sw_event(event_id, nr, nmi, regs, addr);
+2 -1
View File
@@ -14,7 +14,8 @@
#include <asm/page.h> /* kmalloc_sizes.h needs PAGE_SIZE */
#include <asm/cache.h> /* kmalloc_sizes.h needs L1_CACHE_BYTES */
#include <linux/compiler.h>
#include <linux/kmemtrace.h>
#include <trace/events/kmem.h>
#ifndef ARCH_KMALLOC_MINALIGN
/*
+2 -1
View File
@@ -10,9 +10,10 @@
#include <linux/gfp.h>
#include <linux/workqueue.h>
#include <linux/kobject.h>
#include <linux/kmemtrace.h>
#include <linux/kmemleak.h>
#include <trace/events/kmem.h>
enum stat_item {
ALLOC_FASTPATH, /* Allocation from cpu slab */
ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */
-60
View File
@@ -1,60 +0,0 @@
#ifndef _LINUX_TRACE_BOOT_H
#define _LINUX_TRACE_BOOT_H
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/init.h>
/*
* Structure which defines the trace of an initcall
* while it is called.
* You don't have to fill the func field since it is
* only used internally by the tracer.
*/
struct boot_trace_call {
pid_t caller;
char func[KSYM_SYMBOL_LEN];
};
/*
* Structure which defines the trace of an initcall
* while it returns.
*/
struct boot_trace_ret {
char func[KSYM_SYMBOL_LEN];
int result;
unsigned long long duration; /* nsecs */
};
#ifdef CONFIG_BOOT_TRACER
/* Append the traces on the ring-buffer */
extern void trace_boot_call(struct boot_trace_call *bt, initcall_t fn);
extern void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn);
/* Tells the tracer that smp_pre_initcall is finished.
* So we can start the tracing
*/
extern void start_boot_trace(void);
/* Resume the tracing of other necessary events
* such as sched switches
*/
extern void enable_boot_trace(void);
/* Suspend this tracing. Actually, only sched_switches tracing have
* to be suspended. Initcalls doesn't need it.)
*/
extern void disable_boot_trace(void);
#else
static inline
void trace_boot_call(struct boot_trace_call *bt, initcall_t fn) { }
static inline
void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn) { }
static inline void start_boot_trace(void) { }
static inline void enable_boot_trace(void) { }
static inline void disable_boot_trace(void) { }
#endif /* CONFIG_BOOT_TRACER */
#endif /* __LINUX_TRACE_BOOT_H */

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