| Message ID | 20180711063540.91101-2-joel@joelfernandes.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
On Tue, 10 Jul 2018 23:35:39 -0700 Joel Fernandes <joel@joelfernandes.org> wrote: > > Co-developed-by: Erick Reyes <erickreyes@google.com> A co-developer needs to add their signed off by. To specify that Erick is a co-author, you could do: [ Erick is a co-developer of this commit ] Signed-off-by: Add Erick's SOB here. > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> > --- > kernel/trace/Kconfig | 15 ++++++ > kernel/trace/Makefile | 1 + > kernel/trace/preemptirq_delay_test.c | 72 ++++++++++++++++++++++++++++ > 3 files changed, 88 insertions(+) > create mode 100644 kernel/trace/preemptirq_delay_test.c > > diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig > index 8d51351e3149..eb5ab6b511e2 100644 > --- a/kernel/trace/Kconfig > +++ b/kernel/trace/Kconfig > @@ -699,6 +699,21 @@ config RING_BUFFER_STARTUP_TEST > > If unsure, say N > > +config PREEMPTIRQ_DELAY_TEST > + tristate "Preempt / IRQ disable delay thread to test latency tracers" > + depends on m > + help > + Select this option to build a test module that can help test latency > + tracers by executing a preempt or irq disable section with a user > + configurable delay. The module busy waits for the duration of the > + critical section. > + > + For example, the following invocation forces a one-time irq-disabled > + critical section for 500us: > + modprobe preemptirq_delay_test test_mode=irq delay=500000 > + > + If unsure, say N > + > config TRACE_EVAL_MAP_FILE > bool "Show eval mappings for trace events" > depends on TRACING > diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile > index 84a0cb222f20..677540bb1b62 100644 > --- a/kernel/trace/Makefile > +++ b/kernel/trace/Makefile > @@ -36,6 +36,7 @@ obj-$(CONFIG_TRACING_MAP) += tracing_map.o > obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o > obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o > obj-$(CONFIG_PREEMPTIRQ_TRACEPOINTS) += trace_preemptirq.o > +obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o > obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o > obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o > obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o > diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c > new file mode 100644 > index 000000000000..c97a026c0720 > --- /dev/null > +++ b/kernel/trace/preemptirq_delay_test.c > @@ -0,0 +1,72 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Preempt / IRQ disable delay thread to test latency tracers > + * > + * Copyright (C) 2018 Joel Fernandes (Google) <joel@joelfernandes.org> > + */ > + > +#include <linux/delay.h> > +#include <linux/interrupt.h> > +#include <linux/irq.h> > +#include <linux/kernel.h> > +#include <linux/kthread.h> > +#include <linux/ktime.h> > +#include <linux/module.h> > +#include <linux/printk.h> > +#include <linux/string.h> > + > +static ulong delay = 100; > +static char test_mode[10] = "irq"; > + > +module_param_named(delay, delay, ulong, S_IRUGO); > +module_param_string(test_mode, test_mode, 10, S_IRUGO); > +MODULE_PARM_DESC(delay, "Period in microseconds (100 uS default)"); > +MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt or irq (default irq)"); > + > +static void busy_wait(ulong time) > +{ > + ktime_t start, end; > + start = ktime_get(); > + do { > + end = ktime_get(); > + if (kthread_should_stop()) > + break; > + } while (ktime_to_ns(ktime_sub(end, start)) < (time * 1000)); > +} > + > +int preemptirq_delay_run(void *data) > +{ > + unsigned long flags; > + > + if (!strcmp(test_mode, "irq")) { > + local_irq_save(flags); > + busy_wait(delay); > + local_irq_restore(flags); > + } else if (!strcmp(test_mode, "preempt")) { > + preempt_disable(); > + busy_wait(delay); > + preempt_enable(); > + } > + > + return 0; > +} > + > +static int __init preemptirq_delay_init(void) > +{ > + char task_name[50]; > + struct task_struct *test_task; > + > + snprintf(task_name, sizeof(task_name), "%s_test", test_mode); > + > + test_task = kthread_run(preemptirq_delay_run, NULL, task_name); > + return PTR_ERR_OR_ZERO(test_task); > +} > + > +static void __exit preemptirq_delay_exit(void) > +{ > + return; > +} > + > +module_init(preemptirq_delay_init) > +module_exit(preemptirq_delay_exit) > +MODULE_LICENSE("GPL v2"); -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 8d51351e3149..eb5ab6b511e2 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -699,6 +699,21 @@ config RING_BUFFER_STARTUP_TEST If unsure, say N +config PREEMPTIRQ_DELAY_TEST + tristate "Preempt / IRQ disable delay thread to test latency tracers" + depends on m + help + Select this option to build a test module that can help test latency + tracers by executing a preempt or irq disable section with a user + configurable delay. The module busy waits for the duration of the + critical section. + + For example, the following invocation forces a one-time irq-disabled + critical section for 500us: + modprobe preemptirq_delay_test test_mode=irq delay=500000 + + If unsure, say N + config TRACE_EVAL_MAP_FILE bool "Show eval mappings for trace events" depends on TRACING diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 84a0cb222f20..677540bb1b62 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -36,6 +36,7 @@ obj-$(CONFIG_TRACING_MAP) += tracing_map.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o obj-$(CONFIG_PREEMPTIRQ_TRACEPOINTS) += trace_preemptirq.o +obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c new file mode 100644 index 000000000000..c97a026c0720 --- /dev/null +++ b/kernel/trace/preemptirq_delay_test.c @@ -0,0 +1,72 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Preempt / IRQ disable delay thread to test latency tracers + * + * Copyright (C) 2018 Joel Fernandes (Google) <joel@joelfernandes.org> + */ + +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <linux/kthread.h> +#include <linux/ktime.h> +#include <linux/module.h> +#include <linux/printk.h> +#include <linux/string.h> + +static ulong delay = 100; +static char test_mode[10] = "irq"; + +module_param_named(delay, delay, ulong, S_IRUGO); +module_param_string(test_mode, test_mode, 10, S_IRUGO); +MODULE_PARM_DESC(delay, "Period in microseconds (100 uS default)"); +MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt or irq (default irq)"); + +static void busy_wait(ulong time) +{ + ktime_t start, end; + start = ktime_get(); + do { + end = ktime_get(); + if (kthread_should_stop()) + break; + } while (ktime_to_ns(ktime_sub(end, start)) < (time * 1000)); +} + +int preemptirq_delay_run(void *data) +{ + unsigned long flags; + + if (!strcmp(test_mode, "irq")) { + local_irq_save(flags); + busy_wait(delay); + local_irq_restore(flags); + } else if (!strcmp(test_mode, "preempt")) { + preempt_disable(); + busy_wait(delay); + preempt_enable(); + } + + return 0; +} + +static int __init preemptirq_delay_init(void) +{ + char task_name[50]; + struct task_struct *test_task; + + snprintf(task_name, sizeof(task_name), "%s_test", test_mode); + + test_task = kthread_run(preemptirq_delay_run, NULL, task_name); + return PTR_ERR_OR_ZERO(test_task); +} + +static void __exit preemptirq_delay_exit(void) +{ + return; +} + +module_init(preemptirq_delay_init) +module_exit(preemptirq_delay_exit) +MODULE_LICENSE("GPL v2");