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/**
* Copyright (C) ARM Limited 2010-2011. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <trace/events/sched.h>
#include "gator.h"
#define SCHED_OVERFLOW -1
#define SCHED_SWITCH 1
#define SCHED_PROCESS_FREE 2
#define FIELD_TYPE 0
#define FIELD_TIME 1
#define FIELD_PARAM1 2
#define FIELD_PARAM2 3
#define FIELD_PARAM3 4
#define FIELDS_PER_SCHED 5
#define SCHEDSIZE (8*1024)
#define TASK_MAP_ENTRIES 1024 /* must be power of 2 */
#define TASK_MAX_COLLISIONS 2
static DEFINE_PER_CPU(uint64_t *[2], theSchedBuf);
static DEFINE_PER_CPU(int, theSchedSel);
static DEFINE_PER_CPU(int, theSchedPos);
static DEFINE_PER_CPU(int, theSchedErr);
static DEFINE_PER_CPU(uint64_t *, taskname_keys);
void emit_pid_name(uint64_t time, struct task_struct* task)
{
bool found = false;
unsigned long flags;
char taskcomm[TASK_COMM_LEN + 3];
int x, cpu = smp_processor_id();
uint64_t *keys = &(per_cpu(taskname_keys, cpu)[(task->pid & 0xFF) * TASK_MAX_COLLISIONS]);
uint64_t value;
value = gator_chksum_crc32(task->comm);
value = (value << 32) | (uint32_t)task->pid;
// determine if the thread name was emitted already
for (x = 0; x < TASK_MAX_COLLISIONS; x++) {
if (keys[x] == value) {
found = true;
break;
}
}
if (!found) {
// shift values, new value always in front
uint64_t oldv, newv = value;
for (x = 0; x < TASK_MAX_COLLISIONS; x++) {
oldv = keys[x];
keys[x] = newv;
newv = oldv;
}
// emit pid names, cannot use get_task_comm, as it's not exported on all kernel versions
if (strlcpy(taskcomm, task->comm, TASK_COMM_LEN) == TASK_COMM_LEN - 1)
// append ellipses if task->comm has length of TASK_COMM_LEN - 1
strcat(taskcomm, "...");
// disable interrupts to synchronize with hrtimer populating timer buf
local_irq_save(flags);
gator_buffer_write_packed_int(cpu, TIMER_BUF, MESSAGE_PID_NAME);
gator_buffer_write_packed_int64(cpu, TIMER_BUF, time);
gator_buffer_write_packed_int(cpu, TIMER_BUF, task->pid);
gator_buffer_write_string(cpu, TIMER_BUF, taskcomm);
local_irq_restore(flags);
}
}
static void probe_sched_write(int type, int param1, int param2, int param3)
{
unsigned long flags;
int cpu = smp_processor_id();
uint64_t time = gator_get_time();
uint64_t *schedBuf;
int schedPos, cookie = param3;
if (!per_cpu(theSchedBuf, cpu)[per_cpu(theSchedSel, cpu)])
return;
if (param3) {
// do as much work as possible before disabling interrupts
struct task_struct *task = (struct task_struct *)param3;
cookie = get_exec_cookie(cpu, TIMER_BUF, task);
emit_pid_name(time, task);
}
// disable interrupts to synchronize with gator_trace_sched_read(); spinlocks not needed since percpu buffers are used
local_irq_save(flags);
schedPos = per_cpu(theSchedPos, cpu);
schedBuf = per_cpu(theSchedBuf, cpu)[per_cpu(theSchedSel, cpu)];
if (schedPos < (SCHEDSIZE-100)) {
// capture
schedBuf[schedPos+FIELD_TYPE] = type;
schedBuf[schedPos+FIELD_TIME] = time;
schedBuf[schedPos+FIELD_PARAM1] = param1;
schedBuf[schedPos+FIELD_PARAM2] = param2;
schedBuf[schedPos+FIELD_PARAM3] = cookie;
per_cpu(theSchedPos, cpu) = schedPos + FIELDS_PER_SCHED;
} else if (!per_cpu(theSchedErr, cpu)) {
per_cpu(theSchedErr, cpu) = 1;
schedBuf[schedPos+FIELD_TYPE] = SCHED_OVERFLOW;
schedBuf[schedPos+FIELD_TIME] = time;
schedBuf[schedPos+FIELD_PARAM1] = 0;
schedBuf[schedPos+FIELD_PARAM2] = 0;
schedBuf[schedPos+FIELD_PARAM3] = 0;
per_cpu(theSchedPos, cpu) = schedPos + FIELDS_PER_SCHED;
pr_debug("gator: tracepoint overflow\n");
}
local_irq_restore(flags);
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 35)
GATOR_DEFINE_PROBE(sched_switch, TP_PROTO(struct rq *rq, struct task_struct *prev, struct task_struct *next))
#else
GATOR_DEFINE_PROBE(sched_switch, TP_PROTO(struct task_struct *prev, struct task_struct *next))
#endif
{
probe_sched_write(SCHED_SWITCH, next->pid, next->tgid, (int)next);
}
GATOR_DEFINE_PROBE(sched_process_free, TP_PROTO(struct task_struct *p))
{
probe_sched_write(SCHED_PROCESS_FREE, p->pid, 0, 0);
}
int gator_trace_sched_init(void)
{
return 0;
}
int gator_trace_sched_start(void)
{
int cpu, size;
for_each_present_cpu(cpu) {
per_cpu(theSchedSel, cpu) = 0;
per_cpu(theSchedPos, cpu) = 0;
per_cpu(theSchedErr, cpu) = 0;
per_cpu(theSchedBuf, cpu)[0] = kmalloc(SCHEDSIZE * sizeof(uint64_t), GFP_KERNEL);
per_cpu(theSchedBuf, cpu)[1] = kmalloc(SCHEDSIZE * sizeof(uint64_t), GFP_KERNEL);
if (!per_cpu(theSchedBuf, cpu))
return -1;
size = TASK_MAP_ENTRIES * TASK_MAX_COLLISIONS * sizeof(uint64_t);
per_cpu(taskname_keys, cpu) = (uint64_t*)kmalloc(size, GFP_KERNEL);
if (!per_cpu(taskname_keys, cpu))
return -1;
memset(per_cpu(taskname_keys, cpu), 0, size);
}
// register tracepoints
if (GATOR_REGISTER_TRACE(sched_switch))
goto fail_sched_switch;
if (GATOR_REGISTER_TRACE(sched_process_free))
goto fail_sched_process_free;
pr_debug("gator: registered tracepoints\n");
return 0;
// unregister tracepoints on error
fail_sched_process_free:
GATOR_UNREGISTER_TRACE(sched_switch);
fail_sched_switch:
pr_err("gator: tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
return -1;
}
void gator_trace_sched_stop(void)
{
int cpu;
GATOR_UNREGISTER_TRACE(sched_switch);
GATOR_UNREGISTER_TRACE(sched_process_free);
pr_debug("gator: unregistered tracepoints\n");
for_each_present_cpu(cpu) {
kfree(per_cpu(theSchedBuf, cpu)[0]);
kfree(per_cpu(theSchedBuf, cpu)[1]);
per_cpu(theSchedBuf, cpu)[0] = NULL;
per_cpu(theSchedBuf, cpu)[1] = NULL;
kfree(per_cpu(taskname_keys, cpu));
}
}
int gator_trace_sched_read(long long **buffer)
{
int cpu = smp_processor_id();
unsigned long flags;
uint64_t *schedBuf;
int schedPos;
if (!per_cpu(theSchedBuf, cpu)[per_cpu(theSchedSel, cpu)])
return 0;
local_irq_save(flags);
schedBuf = per_cpu(theSchedBuf, cpu)[per_cpu(theSchedSel, cpu)];
schedPos = per_cpu(theSchedPos, cpu);
per_cpu(theSchedSel, cpu) = !per_cpu(theSchedSel, cpu);
per_cpu(theSchedPos, cpu) = 0;
per_cpu(theSchedErr, cpu) = 0;
local_irq_restore(flags);
if (buffer)
*buffer = schedBuf;
return schedPos;
}
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