Add "/proc/xcall/stats" dir, so we can get the xcall prefetch hit ratio on each CPU that initiates a read system call, which is important for performance tuning. Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- fs/proc/base.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) diff --git a/fs/proc/base.c b/fs/proc/base.c index 4c6fdda92fa4..2c05089bfe53 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3592,6 +3592,68 @@ static const struct file_operations proc_pid_sg_level_operations = { #ifdef CONFIG_FAST_SYSCALL bool fast_syscall_enabled(void); +static ssize_t xcall_stats_write(struct file *file, const char __user *buf, + size_t count, loff_t *pos) +{ + int cpu; + + for_each_cpu(cpu, cpu_online_mask) { + *per_cpu_ptr(&xcall_cache_hit, cpu) = 0; + *per_cpu_ptr(&xcall_cache_miss, cpu) = 0; + *per_cpu_ptr(&xcall_cache_wait, cpu) = 0; + } + + return count; +} + +static int xcall_stats_show(struct seq_file *m, void *v) +{ + unsigned long hit = 0, miss = 0, wait = 0; + unsigned int cpu; + u64 percent; + + for_each_cpu(cpu, cpu_online_mask) { + hit = *per_cpu_ptr(&xcall_cache_hit, cpu); + miss = *per_cpu_ptr(&xcall_cache_miss, cpu); + wait = *per_cpu_ptr(&xcall_cache_wait, cpu); + + if (hit == 0 && miss == 0) + continue; + + percent = (hit * 10000ULL) / (hit + miss); + seq_printf(m, "cpu%d epoll cache_{hit,miss,wait}: %ld,%ld,%ld, hit ratio: %3llu.%02llu%%\n", + cpu, hit, miss, wait, percent / 100, percent % 100); + } + return 0; +} + +static int xcall_stats_open(struct inode *inode, struct file *file) +{ + return single_open(file, xcall_stats_show, NULL); +} + +static const struct proc_ops xcall_stats_fops = { + .proc_open = xcall_stats_open, + .proc_read = seq_read, + .proc_write = xcall_stats_write, + .proc_lseek = seq_lseek, + .proc_release = single_release +}; + +static int __init init_xcall_stats_procfs(void) +{ + struct proc_dir_entry *xcall_proc_dir; + + if (!fast_syscall_enabled()) + return 0; + + xcall_proc_dir = proc_mkdir("xcall", NULL); + proc_create("stats", 0444, xcall_proc_dir, &xcall_stats_fops); + return 0; +} + +device_initcall(init_xcall_stats_procfs); + static int xcall_show(struct seq_file *m, void *v) { struct inode *inode = m->private; -- 2.34.1