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#include <linux/sched.h>
#include <linux/module.h>
#include <litmus/ftdev.h>
#include <litmus/litmus.h>
#include <litmus/trace.h>
/******************************************************************************/
/* Allocation */
/******************************************************************************/
static struct ftdev overhead_dev;
#define trace_ts_buf overhead_dev.minor[0].buf
static unsigned int ts_seq_no = 0;
static inline void __save_timestamp_cpu(unsigned long event,
uint8_t type, uint8_t cpu)
{
unsigned int seq_no;
struct timestamp *ts;
seq_no = fetch_and_inc((int *) &ts_seq_no);
if (ft_buffer_start_write(trace_ts_buf, (void**) &ts)) {
ts->event = event;
ts->timestamp = ft_timestamp();
ts->seq_no = seq_no;
ts->cpu = cpu;
ts->task_type = type;
ft_buffer_finish_write(trace_ts_buf, ts);
}
}
static inline void __save_timestamp(unsigned long event,
uint8_t type)
{
__save_timestamp_cpu(event, type, raw_smp_processor_id());
}
/* hack: fake timestamp to user-reported time, and record parts of the PID */
feather_callback void save_timestamp_time(unsigned long event, unsigned long ptr)
{
uint64_t* time = (uint64_t*) ptr;
unsigned int seq_no;
struct timestamp *ts;
seq_no = fetch_and_inc((int *) &ts_seq_no);
if (ft_buffer_start_write(trace_ts_buf, (void**) &ts)) {
ts->event = event;
ts->timestamp = *time;
ts->seq_no = seq_no;
/* type takes lowest byte of PID */
ts->task_type = (uint8_t) current->pid;
/* cpu takes second-lowest byte of PID*/
ts->cpu = (uint8_t) (current->pid >> 8);
ft_buffer_finish_write(trace_ts_buf, ts);
}
}
feather_callback void save_timestamp_pid(unsigned long event)
{
/* Abuse existing fields to partially export PID. */
__save_timestamp_cpu(event,
/* type takes lowest byte of PID */
(uint8_t) current->pid,
/* cpu takes second-lowest byte of PID*/
(uint8_t) (current->pid >> 8));
}
feather_callback void save_timestamp(unsigned long event)
{
__save_timestamp(event, TSK_UNKNOWN);
}
feather_callback void save_timestamp_def(unsigned long event,
unsigned long type)
{
__save_timestamp(event, (uint8_t) type);
}
feather_callback void save_timestamp_task(unsigned long event,
unsigned long t_ptr)
{
int rt = is_realtime((struct task_struct *) t_ptr);
__save_timestamp(event, rt ? TSK_RT : TSK_BE);
}
feather_callback void save_timestamp_cpu(unsigned long event,
unsigned long cpu)
{
__save_timestamp_cpu(event, TSK_UNKNOWN, cpu);
}
/******************************************************************************/
/* DEVICE FILE DRIVER */
/******************************************************************************/
/*
* should be 8M; it is the max we can ask to buddy system allocator (MAX_ORDER)
* and we might not get as much
*/
#define NO_TIMESTAMPS (2 << 11)
static int alloc_timestamp_buffer(struct ftdev* ftdev, unsigned int idx)
{
unsigned int count = NO_TIMESTAMPS;
while (count && !trace_ts_buf) {
printk("time stamp buffer: trying to allocate %u time stamps.\n", count);
ftdev->minor[idx].buf = alloc_ft_buffer(count, sizeof(struct timestamp));
count /= 2;
}
return ftdev->minor[idx].buf ? 0 : -ENOMEM;
}
static void free_timestamp_buffer(struct ftdev* ftdev, unsigned int idx)
{
free_ft_buffer(ftdev->minor[idx].buf);
ftdev->minor[idx].buf = NULL;
}
static int __init init_ft_overhead_trace(void)
{
int err;
printk("Initializing Feather-Trace overhead tracing device.\n");
err = ftdev_init(&overhead_dev, THIS_MODULE, 1, "ft_trace");
if (err)
goto err_out;
overhead_dev.alloc = alloc_timestamp_buffer;
overhead_dev.free = free_timestamp_buffer;
err = register_ftdev(&overhead_dev);
if (err)
goto err_dealloc;
return 0;
err_dealloc:
ftdev_exit(&overhead_dev);
err_out:
printk(KERN_WARNING "Could not register ft_trace module.\n");
return err;
}
static void __exit exit_ft_overhead_trace(void)
{
ftdev_exit(&overhead_dev);
}
module_init(init_ft_overhead_trace);
module_exit(exit_ft_overhead_trace);
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