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Commit bf1c006e authored by Sheetal Sahasrabudhe's avatar Sheetal Sahasrabudhe Committed by Matt Wagantall
Browse files

Perf: arm64: Add L1 counters to tracepoints 



Create tracepoints framework for collecting L1 counters on
per-pid basis.
Add hooks into scheduler to invoke collection.

Change-Id: I04cbf0c526162e70680573f5f365f8b41d3079ed
Signed-off-by: default avatarSheetal Sahasrabudhe <sheetals@codeaurora.org>
parent d9e2557f

arch/arm64/kernel/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -25,7 +25,8 @@ arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o 
arm64-obj-$(CONFIG_MODULES)		+= arm64ksyms.o module.o

arm64-obj-$(CONFIG_SMP)			+= smp.o smp_spin_table.o topology.o

arm64-obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o

arm64-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o perf_debug.o

arm64-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o perf_debug.o 		\

					   perf_trace_counters.o

arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o

arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND)	+= sleep.o suspend.o

arm64-obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o

arch/arm64/kernel/perf_debug.c

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
 */

static char *descriptions =

	" 0 arm64: perf: add debug patch logging framework\n"

	" 1 Perf: arm64: Add L1 counters to tracepoints\n"

;



static ssize_t desc_read(struct file *fp, char __user *buf,

arch/arm64/kernel/perf_trace_counters.c

0 → 100644
+125 −0
Original line number Diff line number Diff line 
/* Copyright (c) 2013-2014, The Linux Foundation. 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 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <linux/uaccess.h>

#include <linux/debugfs.h>

#include <linux/cpu.h>

#include <linux/tracepoint.h>

#include <trace/events/sched.h>

#define CREATE_TRACE_POINTS

#include "perf_trace_counters.h"



static unsigned int tp_pid_state;



DEFINE_PER_CPU(u32, previous_ccnt);

DEFINE_PER_CPU(u32[NUM_L1_CTRS], previous_l1_cnts);

DEFINE_PER_CPU(u32, old_pid);



void tracectr_notifier(void *ignore, struct task_struct *prev,

					struct task_struct *next)

{

	int current_pid;

	u32 cpu = next->on_cpu;



	if (tp_pid_state != 1)

		return;

	current_pid = next->pid;

	if (per_cpu(old_pid, cpu) != -1)

		trace_sched_switch_with_ctrs(per_cpu(old_pid, cpu),

				current_pid);

	per_cpu(old_pid, cpu) = current_pid;

}



static void enable_tp_pid(void)

{

	if (tp_pid_state == 0) {

		tp_pid_state = 1;

		register_trace_sched_switch(tracectr_notifier, NULL);

	}

}



static void disable_tp_pid(void)

{

	if (tp_pid_state == 1) {

		tp_pid_state = 0;

		unregister_trace_sched_switch(tracectr_notifier, NULL);

	}

}



static ssize_t read_enabled_perftp_file_bool(struct file *file,

		char __user *user_buf, size_t count, loff_t *ppos)

{

	char buf[2];

	buf[1] = '\n';

	if (tp_pid_state == 0)

		buf[0] = '0';

	else

		buf[0] = '1';

	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);

}



static ssize_t write_enabled_perftp_file_bool(struct file *file,

		const char __user *user_buf, size_t count, loff_t *ppos)

{

	char buf[32];

	size_t buf_size;



	buf_size = min(count, (sizeof(buf)-1));

	if (copy_from_user(buf, user_buf, buf_size))

		return -EFAULT;

	switch (buf[0]) {

	case 'y':

	case 'Y':

	case '1':

		enable_tp_pid();

		break;

	case 'n':

	case 'N':

	case '0':

		disable_tp_pid();

		break;

	}



	return count;

}



static const struct file_operations fops_perftp = {

	.read =		read_enabled_perftp_file_bool,

	.write =	write_enabled_perftp_file_bool,

	.llseek =	default_llseek,

};



int __init init_tracecounters(void)

{

	struct dentry *dir;

	struct dentry *file;

	unsigned int value = 1;

	int cpu;



	dir = debugfs_create_dir("perf_debug_tp", NULL);

	if (!dir)

		return -ENOMEM;

	file = debugfs_create_file("enabled", 0660, dir,

		&value, &fops_perftp);

	if (!file) {

		debugfs_remove(dir);

		return -ENOMEM;

	}

	for_each_possible_cpu(cpu)

		per_cpu(old_pid, cpu) = -1;

	return 0;

}



int __exit exit_tracecounters(void)

{

	return 0;

}

late_initcall(init_tracecounters);

arch/arm64/kernel/perf_trace_counters.h

0 → 100644
+116 −0
Original line number Diff line number Diff line 
/* Copyright (c) 2013-2014, The Linux Foundation. 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 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#undef TRACE_SYSTEM

#define TRACE_SYSTEM perf_trace_counters



#if !defined(_PERF_TRACE_COUNTERS_H_) || defined(TRACE_HEADER_MULTI_READ)

#define _PERF_TRACE_COUNTERS_H_



/* Ctr index for PMCNTENSET/CLR */

#define CC 0x80000000

#define C0 0x1

#define C1 0x2

#define C2 0x4

#define C3 0x8

#define C_ALL (CC | C0 | C1 | C2 | C3)

#define NUM_L1_CTRS 4



#include <linux/sched.h>

#include <linux/cpumask.h>

#include <linux/tracepoint.h>



DECLARE_PER_CPU(u32, previous_ccnt);

DECLARE_PER_CPU(u32[NUM_L1_CTRS], previous_l1_cnts);

TRACE_EVENT(sched_switch_with_ctrs,



		TP_PROTO(pid_t prev, pid_t next),



		TP_ARGS(prev, next),



		TP_STRUCT__entry(

			__field(pid_t,	old_pid)

			__field(pid_t,	new_pid)

			__field(u32, cctr)

			__field(u32, ctr0)

			__field(u32, ctr1)

			__field(u32, ctr2)

			__field(u32, ctr3)

			__field(u32, lctr0)

			__field(u32, lctr1)

		),



		TP_fast_assign(

			u32 cpu = smp_processor_id();

			u32 i;

			u32 cnten_val;

			u32 total_ccnt = 0;

			u32 total_cnt = 0;

			u32 delta_l1_cnts[NUM_L1_CTRS];

			__entry->old_pid	= prev;

			__entry->new_pid	= next;





			/* Read PMCNTENSET */

			asm volatile("mrs %0, pmcntenset_el0"

							: "=r" (cnten_val));

			/* Disable all the counters that were enabled */

			asm volatile("msr pmcntenclr_el0, %0"

							: : "r" (cnten_val));

			if (cnten_val & CC) {

				asm volatile("mrs %0, pmccntr_el0"

							: "=r" (total_ccnt));

				/* Read value */

				__entry->cctr = total_ccnt -

					per_cpu(previous_ccnt, cpu);

				per_cpu(previous_ccnt, cpu) = total_ccnt;

			}

			for (i = 0; i < NUM_L1_CTRS; i++) {

				if (cnten_val & (1 << i)) {

					/* Select */

					asm volatile("msr pmselr_el0, %0"

							: : "r" (i));

					isb();

					asm volatile("mrs %0, pmxevcntr_el0"

							: "=r" (total_cnt));

					/* Read value */

					delta_l1_cnts[i] = total_cnt -

					  per_cpu(previous_l1_cnts[i], cpu);

					per_cpu(previous_l1_cnts[i], cpu) =

						total_cnt;

				} else

					delta_l1_cnts[i] = 0;

			}

			/* Enable all the counters that were disabled */

			asm volatile("msr pmcntenset_el0, %0"

							: : "r" (cnten_val));



			__entry->ctr0 = delta_l1_cnts[0];

			__entry->ctr1 = delta_l1_cnts[1];

			__entry->ctr2 = delta_l1_cnts[2];

			__entry->ctr3 = delta_l1_cnts[3];

			__entry->lctr0 = 0;

			__entry->lctr1 = 0;

		),



		TP_printk("prev_pid=%d, next_pid=%d, CCNTR: %u, CTR0: %u, CTR1: %u, CTR2: %u, CTR3: %u, L2CTR0: %u, L2CTR1: %u",

				__entry->old_pid, __entry->new_pid,

				__entry->cctr, __entry->ctr0, __entry->ctr1,

				__entry->ctr2, __entry->ctr3,

				__entry->lctr0, __entry->lctr1)

);



#endif

#undef TRACE_INCLUDE_PATH

#define TRACE_INCLUDE_PATH ../../arch/arm64/kernel

#define TRACE_INCLUDE_FILE perf_trace_counters

#include <trace/define_trace.h>