arch/powerpc/oprofile/cell/spu_profiler.c - arm/linux - Git at Google

 /*
  * Cell Broadband Engine OProfile Support
  *
  * (C) Copyright IBM Corporation 2006
  *
  * Authors: Maynard Johnson <maynardj@us.ibm.com>
  *	    Carl Love <carll@us.ibm.com>
  *
  * 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.
  */

 #include <linux/hrtimer.h>
 #include <linux/smp.h>
 #include <linux/slab.h>
 #include <asm/cell-pmu.h>
 #include <asm/time.h>
 #include "pr_util.h"

 #define SCALE_SHIFT 14

 static u32 *samples;

 /* spu_prof_running is a flag used to indicate if spu profiling is enabled
  * or not.  It is set by the routines start_spu_profiling_cycles() and
  * start_spu_profiling_events().  The flag is cleared by the routines
  * stop_spu_profiling_cycles() and stop_spu_profiling_events().  These
  * routines are called via global_start() and global_stop() which are called in
  * op_powerpc_start() and op_powerpc_stop().  These routines are called once
  * per system as a result of the user starting/stopping oprofile.  Hence, only
  * one CPU per user at a time will be changing  the value of spu_prof_running.
  * In general, OProfile does not protect against multiple users trying to run
  * OProfile at a time.
  */
 int spu_prof_running;
 static unsigned int profiling_interval;

 #define NUM_SPU_BITS_TRBUF 16
 #define SPUS_PER_TB_ENTRY   4

 #define SPU_PC_MASK	     0xFFFF

 DEFINE_SPINLOCK(oprof_spu_smpl_arry_lck);
 static unsigned long oprof_spu_smpl_arry_lck_flags;

 void set_spu_profiling_frequency(unsigned int freq_khz, unsigned int cycles_reset)
 {
 	unsigned long ns_per_cyc;

 	if (!freq_khz)
 		freq_khz = ppc_proc_freq/1000;

 	/* To calculate a timeout in nanoseconds, the basic
 	 * formula is ns = cycles_reset * (NSEC_PER_SEC / cpu frequency).
 	 * To avoid floating point math, we use the scale math
 	 * technique as described in linux/jiffies.h.  We use
 	 * a scale factor of SCALE_SHIFT, which provides 4 decimal places
 	 * of precision.  This is close enough for the purpose at hand.
 	 *
 	 * The value of the timeout should be small enough that the hw
 	 * trace buffer will not get more than about 1/3 full for the
 	 * maximum user specified (the LFSR value) hw sampling frequency.
 	 * This is to ensure the trace buffer will never fill even if the
 	 * kernel thread scheduling varies under a heavy system load.
 	 */

 	ns_per_cyc = (USEC_PER_SEC << SCALE_SHIFT)/freq_khz;
 	profiling_interval = (ns_per_cyc * cycles_reset) >> SCALE_SHIFT;

 }

 /*
  * Extract SPU PC from trace buffer entry
  */
 static void spu_pc_extract(int cpu, int entry)
 {
 	/* the trace buffer is 128 bits */
 	u64 trace_buffer[2];
 	u64 spu_mask;
 	int spu;

 	spu_mask = SPU_PC_MASK;

 	/* Each SPU PC is 16 bits; hence, four spus in each of
 	 * the two 64-bit buffer entries that make up the
 	 * 128-bit trace_buffer entry.	Process two 64-bit values
 	 * simultaneously.
 	 * trace[0] SPU PC contents are: 0 1 2 3
 	 * trace[1] SPU PC contents are: 4 5 6 7
 	 */

 	cbe_read_trace_buffer(cpu, trace_buffer);

 	for (spu = SPUS_PER_TB_ENTRY-1; spu >= 0; spu--) {
 		/* spu PC trace entry is upper 16 bits of the
 		 * 18 bit SPU program counter
 		 */
 		samples[spu * TRACE_ARRAY_SIZE + entry]
 			= (spu_mask & trace_buffer[0]) << 2;
 		samples[(spu + SPUS_PER_TB_ENTRY) * TRACE_ARRAY_SIZE + entry]
 			= (spu_mask & trace_buffer[1]) << 2;

 		trace_buffer[0] = trace_buffer[0] >> NUM_SPU_BITS_TRBUF;
 		trace_buffer[1] = trace_buffer[1] >> NUM_SPU_BITS_TRBUF;
 	}
 }

 static int cell_spu_pc_collection(int cpu)
 {
 	u32 trace_addr;
 	int entry;

 	/* process the collected SPU PC for the node */

 	entry = 0;

 	trace_addr = cbe_read_pm(cpu, trace_address);
 	while (!(trace_addr & CBE_PM_TRACE_BUF_EMPTY)) {
 		/* there is data in the trace buffer to process */
 		spu_pc_extract(cpu, entry);

 		entry++;

 		if (entry >= TRACE_ARRAY_SIZE)
 			/* spu_samples is full */
 			break;

 		trace_addr = cbe_read_pm(cpu, trace_address);
 	}

 	return entry;
 }


 static enum hrtimer_restart profile_spus(struct hrtimer *timer)
 {
 	ktime_t kt;
 	int cpu, node, k, num_samples, spu_num;

 	if (!spu_prof_running)
 		goto stop;

 	for_each_online_cpu(cpu) {
 		if (cbe_get_hw_thread_id(cpu))
 			continue;

 		node = cbe_cpu_to_node(cpu);

 		/* There should only be one kernel thread at a time processing
 		 * the samples.	 In the very unlikely case that the processing
 		 * is taking a very long time and multiple kernel threads are
 		 * started to process the samples.  Make sure only one kernel
 		 * thread is working on the samples array at a time.  The
 		 * sample array must be loaded and then processed for a given
 		 * cpu.	 The sample array is not per cpu.
 		 */
 		spin_lock_irqsave(&oprof_spu_smpl_arry_lck,
 				  oprof_spu_smpl_arry_lck_flags);
 		num_samples = cell_spu_pc_collection(cpu);

 		if (num_samples == 0) {
 			spin_unlock_irqrestore(&oprof_spu_smpl_arry_lck,
 					       oprof_spu_smpl_arry_lck_flags);
 			continue;
 		}

 		for (k = 0; k < SPUS_PER_NODE; k++) {
 			spu_num = k + (node * SPUS_PER_NODE);
 			spu_sync_buffer(spu_num,
 					samples + (k * TRACE_ARRAY_SIZE),
 					num_samples);
 		}

 		spin_unlock_irqrestore(&oprof_spu_smpl_arry_lck,
 				       oprof_spu_smpl_arry_lck_flags);

 	}
 	smp_wmb();	/* insure spu event buffer updates are written */
 			/* don't want events intermingled... */

 	kt = profiling_interval;
 	if (!spu_prof_running)
 		goto stop;
 	hrtimer_forward(timer, timer->base->get_time(), kt);
 	return HRTIMER_RESTART;

  stop:
 	printk(KERN_INFO "SPU_PROF: spu-prof timer ending\n");
 	return HRTIMER_NORESTART;
 }

 static struct hrtimer timer;
 /*
  * Entry point for SPU cycle profiling.
  * NOTE:  SPU profiling is done system-wide, not per-CPU.
  *
  * cycles_reset is the count value specified by the user when
  * setting up OProfile to count SPU_CYCLES.
  */
 int start_spu_profiling_cycles(unsigned int cycles_reset)
 {
 	ktime_t kt;

 	pr_debug("timer resolution: %lu\n", TICK_NSEC);
 	kt = profiling_interval;
 	hrtimer_init(&timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	hrtimer_set_expires(&timer, kt);
 	timer.function = profile_spus;

 	/* Allocate arrays for collecting SPU PC samples */
 	samples = kzalloc(SPUS_PER_NODE *
 			  TRACE_ARRAY_SIZE * sizeof(u32), GFP_KERNEL);

 	if (!samples)
 		return -ENOMEM;

 	spu_prof_running = 1;
 	hrtimer_start(&timer, kt, HRTIMER_MODE_REL);
 	schedule_delayed_work(&spu_work, DEFAULT_TIMER_EXPIRE);

 	return 0;
 }

 /*
  * Entry point for SPU event profiling.
  * NOTE:  SPU profiling is done system-wide, not per-CPU.
  *
  * cycles_reset is the count value specified by the user when
  * setting up OProfile to count SPU_CYCLES.
  */
 void start_spu_profiling_events(void)
 {
 	spu_prof_running = 1;
 	schedule_delayed_work(&spu_work, DEFAULT_TIMER_EXPIRE);

 	return;
 }

 void stop_spu_profiling_cycles(void)
 {
 	spu_prof_running = 0;
 	hrtimer_cancel(&timer);
 	kfree(samples);
 	pr_debug("SPU_PROF: stop_spu_profiling_cycles issued\n");
 }

 void stop_spu_profiling_events(void)
 {
 	spu_prof_running = 0;
 }
	/*
	* Cell Broadband Engine OProfile Support
	*
	* (C) Copyright IBM Corporation 2006
	*
	* Authors: Maynard Johnson <maynardj@us.ibm.com>
	* Carl Love <carll@us.ibm.com>
	*
	* 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.
	*/

	#include <linux/hrtimer.h>
	#include <linux/smp.h>
	#include <linux/slab.h>
	#include <asm/cell-pmu.h>
	#include <asm/time.h>
	#include "pr_util.h"

	#define SCALE_SHIFT 14

	static u32 *samples;

	/* spu_prof_running is a flag used to indicate if spu profiling is enabled
	* or not. It is set by the routines start_spu_profiling_cycles() and
	* start_spu_profiling_events(). The flag is cleared by the routines
	* stop_spu_profiling_cycles() and stop_spu_profiling_events(). These
	* routines are called via global_start() and global_stop() which are called in
	* op_powerpc_start() and op_powerpc_stop(). These routines are called once
	* per system as a result of the user starting/stopping oprofile. Hence, only
	* one CPU per user at a time will be changing the value of spu_prof_running.
	* In general, OProfile does not protect against multiple users trying to run
	* OProfile at a time.
	*/
	int spu_prof_running;
	static unsigned int profiling_interval;

	#define NUM_SPU_BITS_TRBUF 16
	#define SPUS_PER_TB_ENTRY 4

	#define SPU_PC_MASK 0xFFFF

	DEFINE_SPINLOCK(oprof_spu_smpl_arry_lck);
	static unsigned long oprof_spu_smpl_arry_lck_flags;

	void set_spu_profiling_frequency(unsigned int freq_khz, unsigned int cycles_reset)
	{
	unsigned long ns_per_cyc;

	if (!freq_khz)
	freq_khz = ppc_proc_freq/1000;

	/* To calculate a timeout in nanoseconds, the basic
	* formula is ns = cycles_reset * (NSEC_PER_SEC / cpu frequency).
	* To avoid floating point math, we use the scale math
	* technique as described in linux/jiffies.h. We use
	* a scale factor of SCALE_SHIFT, which provides 4 decimal places
	* of precision. This is close enough for the purpose at hand.
	*
	* The value of the timeout should be small enough that the hw
	* trace buffer will not get more than about 1/3 full for the
	* maximum user specified (the LFSR value) hw sampling frequency.
	* This is to ensure the trace buffer will never fill even if the
	* kernel thread scheduling varies under a heavy system load.
	*/

	ns_per_cyc = (USEC_PER_SEC << SCALE_SHIFT)/freq_khz;
	profiling_interval = (ns_per_cyc * cycles_reset) >> SCALE_SHIFT;

	}

	/*
	* Extract SPU PC from trace buffer entry
	*/
	static void spu_pc_extract(int cpu, int entry)
	{
	/* the trace buffer is 128 bits */
	u64 trace_buffer[2];
	u64 spu_mask;
	int spu;

	spu_mask = SPU_PC_MASK;

	/* Each SPU PC is 16 bits; hence, four spus in each of
	* the two 64-bit buffer entries that make up the
	* 128-bit trace_buffer entry. Process two 64-bit values
	* simultaneously.
	* trace[0] SPU PC contents are: 0 1 2 3
	* trace[1] SPU PC contents are: 4 5 6 7
	*/

	cbe_read_trace_buffer(cpu, trace_buffer);

	for (spu = SPUS_PER_TB_ENTRY-1; spu >= 0; spu--) {
	/* spu PC trace entry is upper 16 bits of the
	* 18 bit SPU program counter
	*/
	samples[spu * TRACE_ARRAY_SIZE + entry]
	= (spu_mask & trace_buffer[0]) << 2;
	samples[(spu + SPUS_PER_TB_ENTRY) * TRACE_ARRAY_SIZE + entry]
	= (spu_mask & trace_buffer[1]) << 2;

	trace_buffer[0] = trace_buffer[0] >> NUM_SPU_BITS_TRBUF;
	trace_buffer[1] = trace_buffer[1] >> NUM_SPU_BITS_TRBUF;
	}
	}

	static int cell_spu_pc_collection(int cpu)
	{
	u32 trace_addr;
	int entry;

	/* process the collected SPU PC for the node */

	entry = 0;

	trace_addr = cbe_read_pm(cpu, trace_address);
	while (!(trace_addr & CBE_PM_TRACE_BUF_EMPTY)) {
	/* there is data in the trace buffer to process */
	spu_pc_extract(cpu, entry);

	entry++;

	if (entry >= TRACE_ARRAY_SIZE)
	/* spu_samples is full */
	break;

	trace_addr = cbe_read_pm(cpu, trace_address);
	}

	return entry;
	}


	static enum hrtimer_restart profile_spus(struct hrtimer *timer)
	{
	ktime_t kt;
	int cpu, node, k, num_samples, spu_num;

	if (!spu_prof_running)
	goto stop;

	for_each_online_cpu(cpu) {
	if (cbe_get_hw_thread_id(cpu))
	continue;

	node = cbe_cpu_to_node(cpu);

	/* There should only be one kernel thread at a time processing
	* the samples. In the very unlikely case that the processing
	* is taking a very long time and multiple kernel threads are
	* started to process the samples. Make sure only one kernel
	* thread is working on the samples array at a time. The
	* sample array must be loaded and then processed for a given
	* cpu. The sample array is not per cpu.
	*/
	spin_lock_irqsave(&oprof_spu_smpl_arry_lck,
	oprof_spu_smpl_arry_lck_flags);
	num_samples = cell_spu_pc_collection(cpu);

	if (num_samples == 0) {
	spin_unlock_irqrestore(&oprof_spu_smpl_arry_lck,
	oprof_spu_smpl_arry_lck_flags);
	continue;
	}

	for (k = 0; k < SPUS_PER_NODE; k++) {
	spu_num = k + (node * SPUS_PER_NODE);
	spu_sync_buffer(spu_num,
	samples + (k * TRACE_ARRAY_SIZE),
	num_samples);
	}

	spin_unlock_irqrestore(&oprof_spu_smpl_arry_lck,
	oprof_spu_smpl_arry_lck_flags);

	}
	smp_wmb(); /* insure spu event buffer updates are written */
	/* don't want events intermingled... */

	kt = profiling_interval;
	if (!spu_prof_running)
	goto stop;
	hrtimer_forward(timer, timer->base->get_time(), kt);
	return HRTIMER_RESTART;

	stop:
	printk(KERN_INFO "SPU_PROF: spu-prof timer ending\n");
	return HRTIMER_NORESTART;
	}

	static struct hrtimer timer;
	/*
	* Entry point for SPU cycle profiling.
	* NOTE: SPU profiling is done system-wide, not per-CPU.
	*
	* cycles_reset is the count value specified by the user when
	* setting up OProfile to count SPU_CYCLES.
	*/
	int start_spu_profiling_cycles(unsigned int cycles_reset)
	{
	ktime_t kt;

	pr_debug("timer resolution: %lu\n", TICK_NSEC);
	kt = profiling_interval;
	hrtimer_init(&timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	hrtimer_set_expires(&timer, kt);
	timer.function = profile_spus;

	/* Allocate arrays for collecting SPU PC samples */
	samples = kzalloc(SPUS_PER_NODE *
	TRACE_ARRAY_SIZE * sizeof(u32), GFP_KERNEL);

	if (!samples)
	return -ENOMEM;

	spu_prof_running = 1;
	hrtimer_start(&timer, kt, HRTIMER_MODE_REL);
	schedule_delayed_work(&spu_work, DEFAULT_TIMER_EXPIRE);

	return 0;
	}

	/*
	* Entry point for SPU event profiling.
	* NOTE: SPU profiling is done system-wide, not per-CPU.
	*
	* cycles_reset is the count value specified by the user when
	* setting up OProfile to count SPU_CYCLES.
	*/
	void start_spu_profiling_events(void)
	{
	spu_prof_running = 1;
	schedule_delayed_work(&spu_work, DEFAULT_TIMER_EXPIRE);

	return;
	}

	void stop_spu_profiling_cycles(void)
	{
	spu_prof_running = 0;
	hrtimer_cancel(&timer);
	kfree(samples);
	pr_debug("SPU_PROF: stop_spu_profiling_cycles issued\n");
	}

	void stop_spu_profiling_events(void)
	{
	spu_prof_running = 0;
	}