diff options
Diffstat (limited to 'drivers/gator/gator_events_sched.c')
-rw-r--r-- | drivers/gator/gator_events_sched.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/drivers/gator/gator_events_sched.c b/drivers/gator/gator_events_sched.c new file mode 100644 index 00000000000..9bed3641dbb --- /dev/null +++ b/drivers/gator/gator_events_sched.c @@ -0,0 +1,114 @@ +/** + * Copyright (C) ARM Limited 2010-2012. 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 "gator.h" +#include <trace/events/sched.h> + +#define SCHED_SWITCH 0 +#define SCHED_TOTAL (SCHED_SWITCH+1) + +static ulong sched_switch_enabled; +static ulong sched_switch_key; +static DEFINE_PER_CPU(int[SCHED_TOTAL], schedCnt); +static DEFINE_PER_CPU(int[SCHED_TOTAL * 2], schedGet); + +#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 +{ + unsigned long flags; + + // disable interrupts to synchronize with gator_events_sched_read() + // spinlocks not needed since percpu buffers are used + local_irq_save(flags); + per_cpu(schedCnt, smp_processor_id())[SCHED_SWITCH]++; + local_irq_restore(flags); +} + +static int gator_events_sched_create_files(struct super_block *sb, struct dentry *root) +{ + struct dentry *dir; + + /* switch */ + dir = gatorfs_mkdir(sb, root, "Linux_sched_switch"); + if (!dir) { + return -1; + } + gatorfs_create_ulong(sb, dir, "enabled", &sched_switch_enabled); + gatorfs_create_ro_ulong(sb, dir, "key", &sched_switch_key); + + return 0; +} + +static int gator_events_sched_start(void) +{ + // register tracepoints + if (sched_switch_enabled) + if (GATOR_REGISTER_TRACE(sched_switch)) + goto sched_switch_exit; + pr_debug("gator: registered scheduler event tracepoints\n"); + + return 0; + + // unregister tracepoints on error +sched_switch_exit: + pr_err("gator: scheduler event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n"); + + return -1; +} + +static void gator_events_sched_stop(void) +{ + if (sched_switch_enabled) + GATOR_UNREGISTER_TRACE(sched_switch); + pr_debug("gator: unregistered scheduler event tracepoints\n"); + + sched_switch_enabled = 0; +} + +static int gator_events_sched_read(int **buffer) +{ + unsigned long flags; + int len, value; + int cpu = smp_processor_id(); + + len = 0; + if (sched_switch_enabled) { + local_irq_save(flags); + value = per_cpu(schedCnt, cpu)[SCHED_SWITCH]; + per_cpu(schedCnt, cpu)[SCHED_SWITCH] = 0; + local_irq_restore(flags); + per_cpu(schedGet, cpu)[len++] = sched_switch_key; + per_cpu(schedGet, cpu)[len++] = value; + } + + if (buffer) + *buffer = per_cpu(schedGet, cpu); + + return len; +} + +static struct gator_interface gator_events_sched_interface = { + .create_files = gator_events_sched_create_files, + .start = gator_events_sched_start, + .stop = gator_events_sched_stop, + .read = gator_events_sched_read, +}; + +int gator_events_sched_init(void) +{ + sched_switch_enabled = 0; + + sched_switch_key = gator_events_get_key(); + + return gator_events_install(&gator_events_sched_interface); +} +gator_events_init(gator_events_sched_init); |