Revision dda50e716dc9451f40eebfb2902c260e4f62cf34 authored by Andi Kleen on 17 May 2005, 04:53:25 UTC, committed by Linus Torvalds on 17 May 2005, 14:59:14 UTC
The new TSC sync algorithm recently submitted did not work too well. The result was that some MP machines where the TSC came up of the BIOS very unsynchronized and that did not have HPET support were nearly unusable because the time would jump forwards and backwards between CPUs. After a lot of research ;-) and some more prototypes I ended up with just using the one from IA64 which looks best. It has some internal self tuning that should adapt to changing interconnect latencies. It holds up in my tests so far. I believe it was originally written by David Mosberger, I just ported it over to x86-64. See the inline comment for a description. This cleans up the code because it uses smp_call_function for syncing instead of having custom hooks in SMP bootup. Please note that the cycle numbers it outputs are too optimistic because they do not take into account the latency of WRMSR and RDTSC, which can be hundreds of cycles. It seems to be able to sync a dual Opteron to 200-300 cycles, which is probably good enough. There is a timing window during AP bootup where interrupts can see inconsistent time before the TSC is synced. It is hard to avoid unfortunately because we can only do the TSC sync after some setup, and we need to enable interrupts before that. I just ignored it for now. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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oprofilefs.c
/**
* @file oprofilefs.c
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon
*
* A simple filesystem for configuration and
* access of oprofile.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/oprofile.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <asm/uaccess.h>
#include "oprof.h"
#define OPROFILEFS_MAGIC 0x6f70726f
DEFINE_SPINLOCK(oprofilefs_lock);
static struct inode * oprofilefs_get_inode(struct super_block * sb, int mode)
{
struct inode * inode = new_inode(sb);
if (inode) {
inode->i_mode = mode;
inode->i_uid = 0;
inode->i_gid = 0;
inode->i_blksize = PAGE_CACHE_SIZE;
inode->i_blocks = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}
return inode;
}
static struct super_operations s_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
};
ssize_t oprofilefs_str_to_user(char const * str, char __user * buf, size_t count, loff_t * offset)
{
return simple_read_from_buffer(buf, count, offset, str, strlen(str));
}
#define TMPBUFSIZE 50
ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user * buf, size_t count, loff_t * offset)
{
char tmpbuf[TMPBUFSIZE];
size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
if (maxlen > TMPBUFSIZE)
maxlen = TMPBUFSIZE;
return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
}
int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, size_t count)
{
char tmpbuf[TMPBUFSIZE];
if (!count)
return 0;
if (count > TMPBUFSIZE - 1)
return -EINVAL;
memset(tmpbuf, 0x0, TMPBUFSIZE);
if (copy_from_user(tmpbuf, buf, count))
return -EFAULT;
spin_lock(&oprofilefs_lock);
*val = simple_strtoul(tmpbuf, NULL, 0);
spin_unlock(&oprofilefs_lock);
return 0;
}
static ssize_t ulong_read_file(struct file * file, char __user * buf, size_t count, loff_t * offset)
{
unsigned long * val = file->private_data;
return oprofilefs_ulong_to_user(*val, buf, count, offset);
}
static ssize_t ulong_write_file(struct file * file, char const __user * buf, size_t count, loff_t * offset)
{
unsigned long * value = file->private_data;
int retval;
if (*offset)
return -EINVAL;
retval = oprofilefs_ulong_from_user(value, buf, count);
if (retval)
return retval;
return count;
}
static int default_open(struct inode * inode, struct file * filp)
{
if (inode->u.generic_ip)
filp->private_data = inode->u.generic_ip;
return 0;
}
static struct file_operations ulong_fops = {
.read = ulong_read_file,
.write = ulong_write_file,
.open = default_open,
};
static struct file_operations ulong_ro_fops = {
.read = ulong_read_file,
.open = default_open,
};
static struct dentry * __oprofilefs_create_file(struct super_block * sb,
struct dentry * root, char const * name, struct file_operations * fops,
int perm)
{
struct dentry * dentry;
struct inode * inode;
dentry = d_alloc_name(root, name);
if (!dentry)
return NULL;
inode = oprofilefs_get_inode(sb, S_IFREG | perm);
if (!inode) {
dput(dentry);
return NULL;
}
inode->i_fop = fops;
d_add(dentry, inode);
return dentry;
}
int oprofilefs_create_ulong(struct super_block * sb, struct dentry * root,
char const * name, unsigned long * val)
{
struct dentry * d = __oprofilefs_create_file(sb, root, name,
&ulong_fops, 0644);
if (!d)
return -EFAULT;
d->d_inode->u.generic_ip = val;
return 0;
}
int oprofilefs_create_ro_ulong(struct super_block * sb, struct dentry * root,
char const * name, unsigned long * val)
{
struct dentry * d = __oprofilefs_create_file(sb, root, name,
&ulong_ro_fops, 0444);
if (!d)
return -EFAULT;
d->d_inode->u.generic_ip = val;
return 0;
}
static ssize_t atomic_read_file(struct file * file, char __user * buf, size_t count, loff_t * offset)
{
atomic_t * val = file->private_data;
return oprofilefs_ulong_to_user(atomic_read(val), buf, count, offset);
}
static struct file_operations atomic_ro_fops = {
.read = atomic_read_file,
.open = default_open,
};
int oprofilefs_create_ro_atomic(struct super_block * sb, struct dentry * root,
char const * name, atomic_t * val)
{
struct dentry * d = __oprofilefs_create_file(sb, root, name,
&atomic_ro_fops, 0444);
if (!d)
return -EFAULT;
d->d_inode->u.generic_ip = val;
return 0;
}
int oprofilefs_create_file(struct super_block * sb, struct dentry * root,
char const * name, struct file_operations * fops)
{
if (!__oprofilefs_create_file(sb, root, name, fops, 0644))
return -EFAULT;
return 0;
}
int oprofilefs_create_file_perm(struct super_block * sb, struct dentry * root,
char const * name, struct file_operations * fops, int perm)
{
if (!__oprofilefs_create_file(sb, root, name, fops, perm))
return -EFAULT;
return 0;
}
struct dentry * oprofilefs_mkdir(struct super_block * sb,
struct dentry * root, char const * name)
{
struct dentry * dentry;
struct inode * inode;
dentry = d_alloc_name(root, name);
if (!dentry)
return NULL;
inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
if (!inode) {
dput(dentry);
return NULL;
}
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
d_add(dentry, inode);
return dentry;
}
static int oprofilefs_fill_super(struct super_block * sb, void * data, int silent)
{
struct inode * root_inode;
struct dentry * root_dentry;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = OPROFILEFS_MAGIC;
sb->s_op = &s_ops;
sb->s_time_gran = 1;
root_inode = oprofilefs_get_inode(sb, S_IFDIR | 0755);
if (!root_inode)
return -ENOMEM;
root_inode->i_op = &simple_dir_inode_operations;
root_inode->i_fop = &simple_dir_operations;
root_dentry = d_alloc_root(root_inode);
if (!root_dentry) {
iput(root_inode);
return -ENOMEM;
}
sb->s_root = root_dentry;
oprofile_create_files(sb, root_dentry);
// FIXME: verify kill_litter_super removes our dentries
return 0;
}
static struct super_block *oprofilefs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return get_sb_single(fs_type, flags, data, oprofilefs_fill_super);
}
static struct file_system_type oprofilefs_type = {
.owner = THIS_MODULE,
.name = "oprofilefs",
.get_sb = oprofilefs_get_sb,
.kill_sb = kill_litter_super,
};
int __init oprofilefs_register(void)
{
return register_filesystem(&oprofilefs_type);
}
void __exit oprofilefs_unregister(void)
{
unregister_filesystem(&oprofilefs_type);
}
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