diff options
Diffstat (limited to 'drivers/gator/gator_trace_sched.c')
-rw-r--r-- | drivers/gator/gator_trace_sched.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/gator/gator_trace_sched.c b/drivers/gator/gator_trace_sched.c new file mode 100644 index 000000000000..655008628933 --- /dev/null +++ b/drivers/gator/gator_trace_sched.c @@ -0,0 +1,297 @@ +/** + * Copyright (C) ARM Limited 2010-2014. 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 TASK_MAP_ENTRIES 1024 /* must be power of 2 */ +#define TASK_MAX_COLLISIONS 2 + +enum { + STATE_WAIT_ON_OTHER = 0, + STATE_CONTENTION, + STATE_WAIT_ON_IO, + CPU_WAIT_TOTAL +}; + +static DEFINE_PER_CPU(uint64_t *, taskname_keys); +static DEFINE_PER_CPU(int, collecting); + +// this array is never read as the cpu wait charts are derived counters +// the files are needed, nonetheless, to show that these counters are available +static ulong cpu_wait_enabled[CPU_WAIT_TOTAL]; +static ulong sched_cpu_key[CPU_WAIT_TOTAL]; + +static int sched_trace_create_files(struct super_block *sb, struct dentry *root) +{ + struct dentry *dir; + + // CPU Wait - Contention + dir = gatorfs_mkdir(sb, root, "Linux_cpu_wait_contention"); + if (!dir) { + return -1; + } + gatorfs_create_ulong(sb, dir, "enabled", &cpu_wait_enabled[STATE_CONTENTION]); + gatorfs_create_ro_ulong(sb, dir, "key", &sched_cpu_key[STATE_CONTENTION]); + + // CPU Wait - I/O + dir = gatorfs_mkdir(sb, root, "Linux_cpu_wait_io"); + if (!dir) { + return -1; + } + gatorfs_create_ulong(sb, dir, "enabled", &cpu_wait_enabled[STATE_WAIT_ON_IO]); + gatorfs_create_ro_ulong(sb, dir, "key", &sched_cpu_key[STATE_WAIT_ON_IO]); + + return 0; +} + +static void emit_pid_name(struct task_struct *task) +{ + bool found = false; + char taskcomm[TASK_COMM_LEN + 3]; + unsigned long x, cpu = get_physical_cpu(); + 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, "..."); + } + + marshal_thread_name(task->pid, taskcomm); + } +} + +static void collect_counters(u64 time, struct task_struct *task) +{ + int *buffer, len, cpu = get_physical_cpu(); + long long *buffer64; + struct gator_interface *gi; + + if (marshal_event_header(time)) { + list_for_each_entry(gi, &gator_events, list) { + if (gi->read) { + len = gi->read(&buffer); + marshal_event(len, buffer); + } else if (gi->read64) { + len = gi->read64(&buffer64); + marshal_event64(len, buffer64); + } + if (gi->read_proc && task != NULL) { + len = gi->read_proc(&buffer64, task); + marshal_event64(len, buffer64); + } + } + // Only check after writing all counters so that time and corresponding counters appear in the same frame + buffer_check(cpu, BLOCK_COUNTER_BUF, time); + + // Commit buffers on timeout + if (gator_live_rate > 0 && time >= per_cpu(gator_buffer_commit_time, cpu)) { + static const int buftypes[] = { NAME_BUF, COUNTER_BUF, BLOCK_COUNTER_BUF, SCHED_TRACE_BUF, ACTIVITY_BUF }; + int i; + + for (i = 0; i < ARRAY_SIZE(buftypes); ++i) { + gator_commit_buffer(cpu, buftypes[i], time); + } + + // spinlocks are noops on uniprocessor machines and mutexes do not work in sched_switch context in + // RT-Preempt full, so disable proactive flushing of the annotate frame on uniprocessor machines. +#ifdef CONFIG_SMP + // Try to preemptively flush the annotate buffer to reduce the chance of the buffer being full + if (on_primary_core() && spin_trylock(&annotate_lock)) { + gator_commit_buffer(0, ANNOTATE_BUF, time); + spin_unlock(&annotate_lock); + } +#endif + } + } +} + +// special case used during a suspend of the system +static void trace_sched_insert_idle(void) +{ + marshal_sched_trace_switch(0, 0); +} + +static void gator_trace_emit_link(struct task_struct *p) +{ + int cookie; + int cpu = get_physical_cpu(); + + cookie = get_exec_cookie(cpu, p); + emit_pid_name(p); + + marshal_link(cookie, p->tgid, p->pid); +} + +GATOR_DEFINE_PROBE(sched_process_fork, TP_PROTO(struct task_struct *parent, struct task_struct *child)) +{ + gator_trace_emit_link(child); +} + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0) +GATOR_DEFINE_PROBE(sched_process_exec, TP_PROTO(struct task_struct *p, pid_t old_pid, struct linux_binprm *bprm)) +{ + gator_trace_emit_link(p); +} +#endif + +#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 +{ + int state; + int cpu = get_physical_cpu(); + + per_cpu(in_scheduler_context, cpu) = true; + + // do as much work as possible before disabling interrupts + if (prev->state == TASK_RUNNING) { + state = STATE_CONTENTION; + } else if (prev->in_iowait) { + state = STATE_WAIT_ON_IO; + } else { + state = STATE_WAIT_ON_OTHER; + } + + per_cpu(collecting, cpu) = 1; + collect_counters(gator_get_time(), prev); + per_cpu(collecting, cpu) = 0; + +#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0) + gator_trace_emit_link(next); +#endif + marshal_sched_trace_switch(next->pid, state); + + per_cpu(in_scheduler_context, cpu) = false; +} + +GATOR_DEFINE_PROBE(sched_process_free, TP_PROTO(struct task_struct *p)) +{ + marshal_sched_trace_exit(p->tgid, p->pid); +} + +static void do_nothing(void *info) +{ + // Intentionally do nothing + (void)info; +} + +static int register_scheduler_tracepoints(void) +{ + // register tracepoints + if (GATOR_REGISTER_TRACE(sched_process_fork)) + goto fail_sched_process_fork; +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0) + if (GATOR_REGISTER_TRACE(sched_process_exec)) + goto fail_sched_process_exec; +#endif + 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"); + + // Now that the scheduler tracepoint is registered, force a context switch + // on all cpus to capture what is currently running. + on_each_cpu(do_nothing, NULL, 0); + + return 0; + + // unregister tracepoints on error +fail_sched_process_free: + GATOR_UNREGISTER_TRACE(sched_switch); +fail_sched_switch: + GATOR_UNREGISTER_TRACE(sched_process_fork); +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0) +fail_sched_process_exec: + GATOR_UNREGISTER_TRACE(sched_process_exec); +#endif +fail_sched_process_fork: + pr_err("gator: tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n"); + + return -1; +} + +static void unregister_scheduler_tracepoints(void) +{ + GATOR_UNREGISTER_TRACE(sched_process_fork); +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0) + GATOR_UNREGISTER_TRACE(sched_process_exec); +#endif + GATOR_UNREGISTER_TRACE(sched_switch); + GATOR_UNREGISTER_TRACE(sched_process_free); + pr_debug("gator: unregistered tracepoints\n"); +} + +static void gator_trace_sched_stop(void) +{ + int cpu; + + unregister_scheduler_tracepoints(); + + for_each_present_cpu(cpu) { + kfree(per_cpu(taskname_keys, cpu)); + } +} + +static int gator_trace_sched_start(void) +{ + int cpu, size; + int ret; + + for_each_present_cpu(cpu) { + 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); + } + + ret = register_scheduler_tracepoints(); + + return ret; +} + +static void gator_trace_sched_offline(void) +{ + trace_sched_insert_idle(); +} + +static void gator_trace_sched_init(void) +{ + int i; + for (i = 0; i < CPU_WAIT_TOTAL; i++) { + cpu_wait_enabled[i] = 0; + sched_cpu_key[i] = gator_events_get_key(); + } +} |