From: Soren Sandmann <[EMAIL PROTECTED]> Subject: [PATCH] x86: add the debugfs interface for the sysprof tool
The sysprof tool is a very easy to use GUI tool to find out where userspace is spending CPU time. See http://www.daimi.au.dk/~sandmann/sysprof/ for more information and screenshots on this tool. Sysprof needs a 200 line kernel module to do it's work, this module puts some simple profiling data into debugfs. Signed-off-by: Soren Sandmann <[EMAIL PROTECTED]> Signed-off-by: Arjan van de Ven <[EMAIL PROTECTED]> --- arch/x86/Kconfig.debug | 10 ++ arch/x86/kernel/Makefile | 2 + arch/x86/kernel/sysprof.c | 200 +++++++++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/sysprof.h | 34 ++++++++ 4 files changed, 246 insertions(+), 0 deletions(-) create mode 100644 arch/x86/kernel/sysprof.c create mode 100644 arch/x86/kernel/sysprof.h diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 12c98ea..8eb06c0 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -206,6 +206,16 @@ config MMIOTRACE_TEST Say N, unless you absolutely know what you are doing. +config SYSPROF + tristate "Enable sysprof userland performance sampler" + depends on PROFILING + help + This option enables the sysprof debugfs file that is used by the + sysprof tool. sysprof is a tool to show where in userspace CPU + time is spent. + + When in doubt, say N + # # IO delay types: # diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 4a4260c..1e8fb66 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -80,6 +80,8 @@ obj-$(CONFIG_DEBUG_NX_TEST) += test_nx.o obj-$(CONFIG_VMI) += vmi_32.o vmiclock_32.o obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt_patch_$(BITS).o +obj-$(CONFIG_SYSPROF) += sysprof.o + ifdef CONFIG_INPUT_PCSPKR obj-y += pcspeaker.o endif diff --git a/arch/x86/kernel/sysprof.c b/arch/x86/kernel/sysprof.c new file mode 100644 index 0000000..6220b9f --- /dev/null +++ b/arch/x86/kernel/sysprof.c @@ -0,0 +1,200 @@ +/* -*- c-basic-offset: 8 -*- */ + +/* Sysprof -- Sampling, systemwide CPU profiler + * Copyright 2004, Red Hat, Inc. + * Copyright 2004, 2005, Soeren Sandmann + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/proc_fs.h> +#include <linux/poll.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> +#include <linux/profile.h> +#include <linux/debugfs.h> +#include <asm/uaccess.h> +#include <asm/atomic.h> + +#include "sysprof.h" + +#define SAMPLES_PER_SECOND (200) +#define INTERVAL ((HZ <= SAMPLES_PER_SECOND)? 1 : (HZ / SAMPLES_PER_SECOND)) +#define N_TRACES 256 + +static struct sysprof_stacktrace stack_traces[N_TRACES]; +static struct sysprof_stacktrace *head = &stack_traces[0]; +static struct sysprof_stacktrace *tail = &stack_traces[0]; +static DECLARE_WAIT_QUEUE_HEAD(wait_for_trace); +static DECLARE_WAIT_QUEUE_HEAD(wait_for_exit); + +struct userspace_reader { + struct task_struct *task; + unsigned long cache_address; + unsigned long *cache; +}; + +struct stack_frame; + +struct stack_frame { + struct stack_frame __user *next; + unsigned long return_address; +}; + +static int read_frame(struct stack_frame __user *frame_pointer, + struct stack_frame *frame) +{ + if (__copy_from_user_inatomic(frame, frame_pointer, + sizeof(struct stack_frame))) + return 1; + return 0; +} + +static DEFINE_PER_CPU(int, n_samples); + +static int timer_notify(struct pt_regs *regs) +{ + struct sysprof_stacktrace *trace = head; + int i; + int is_user; + static atomic_t in_timer_notify = ATOMIC_INIT(1); + int n; + + n = ++get_cpu_var(n_samples); + put_cpu_var(n_samples); + + if (n % INTERVAL != 0) + return 0; + + /* 0: locked, 1: unlocked */ + + if (!atomic_dec_and_test(&in_timer_notify)) + goto out; + + is_user = user_mode(regs); + + if (!current || current->pid == 0) + goto out; + + if (is_user && current->state != TASK_RUNNING) + goto out; + + if (!is_user) { + /* kernel */ + trace->pid = current->pid; + trace->truncated = 0; + trace->n_addresses = 1; + + /* 0x1 is taken by sysprof to mean "in kernel" */ + trace->addresses[0] = 0x1; + } else { + struct stack_frame __user *frame_pointer; + struct stack_frame frame; + memset(trace, 0, sizeof(struct sysprof_stacktrace)); + + trace->pid = current->pid; + trace->truncated = 0; + + i = 0; + + trace->addresses[i++] = regs->ip; + + frame_pointer = (struct stack_frame __user *)regs->bp; + + while (read_frame(frame_pointer, &frame) == 0 && + i < SYSPROF_MAX_ADDRESSES && + (unsigned long)frame_pointer >= regs->sp) { + trace->addresses[i++] = frame.return_address; + frame_pointer = frame.next; + } + + trace->n_addresses = i; + + if (i == SYSPROF_MAX_ADDRESSES) + trace->truncated = 1; + else + trace->truncated = 0; + } + + if (head++ == &stack_traces[N_TRACES - 1]) + head = &stack_traces[0]; + + wake_up(&wait_for_trace); + +out: + atomic_inc(&in_timer_notify); + return 0; +} + +static ssize_t procfile_read(struct file *filp, char __user *buffer, + size_t count, loff_t *ppos) +{ + ssize_t bcount; + if (head == tail) + return -EWOULDBLOCK; + + BUG_ON(tail->pid == 0); + *ppos = 0; + bcount = simple_read_from_buffer(buffer, count, ppos, + tail, sizeof(struct sysprof_stacktrace)); + + if (tail++ == &stack_traces[N_TRACES - 1]) + tail = &stack_traces[0]; + + return bcount; +} + +static unsigned int procfile_poll(struct file *filp, poll_table * poll_table) +{ + if (head != tail) + return POLLIN | POLLRDNORM; + + poll_wait(filp, &wait_for_trace, poll_table); + + if (head != tail) + return POLLIN | POLLRDNORM; + + return 0; +} + +static const struct file_operations sysprof_fops = { + .owner = THIS_MODULE, + .read = procfile_read, + .poll = procfile_poll, +}; + +static struct dentry *debugfs_pe; +int init_module(void) +{ + debugfs_pe = debugfs_create_file("sysprof-trace", 0600, NULL, NULL, + &sysprof_fops); + if (!debugfs_pe) + return -ENODEV; + register_timer_hook(timer_notify); + + return 0; +} + +void cleanup_module(void) +{ + unregister_timer_hook(timer_notify); + debugfs_remove(debugfs_pe); +} + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Soeren Sandmann ([EMAIL PROTECTED])"); +MODULE_DESCRIPTION("Kernel driver for the sysprof performance analysis tool"); diff --git a/arch/x86/kernel/sysprof.h b/arch/x86/kernel/sysprof.h new file mode 100644 index 0000000..6e16d6f --- /dev/null +++ b/arch/x86/kernel/sysprof.h @@ -0,0 +1,34 @@ +/* Sysprof -- Sampling, systemwide CPU profiler + * Copyright 2004, Red Hat, Inc. + * Copyright 2004, 2005, Soeren Sandmann + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#ifndef SYSPROF_MODULE_H +#define SYSPROF_MODULE_H + +#define SYSPROF_MAX_ADDRESSES 512 + +struct sysprof_stacktrace { + int pid; /* -1 if in kernel */ + int truncated; + int n_addresses; /* note: this can be 1 if the process was compiled + * with -fomit-frame-pointer or is otherwise weird + */ + unsigned long addresses[SYSPROF_MAX_ADDRESSES]; +}; + +#endif -- 1.5.4.1 -- If you want to reach me at my work email, use [EMAIL PROTECTED] For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
