linux/samples/ftrace/Makefile

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# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct.o
obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-too.o
obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace-direct-modify.o
obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi.o
obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace-direct-multi-modify.o
ftrace: Add sample with custom ops When reworking core ftrace code or architectural ftrace code, it's often necessary to test/analyse/benchmark a number of ftrace_ops configurations. This patch adds a module which can be used to explore some of those configurations. I'm using this to benchmark various options for changing the way trampolines and handling of ftrace_ops work on arm64, and ensuring other architectures aren't adversely affected. For example, in a QEMU+KVM VM running on a 2GHz Xeon E5-2660 workstation, loading the module in various configurations produces: | # insmod ftrace-ops.ko | ftrace_ops: registering: | relevant ops: 1 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 0 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: NO | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 1681558ns (16ns / call) | # insmod ftrace-ops.ko nr_ops_irrelevant=5 | ftrace_ops: registering: | relevant ops: 1 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 5 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: NO | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 1693042ns (16ns / call) | # insmod ftrace-ops.ko nr_ops_relevant=2 | ftrace_ops: registering: | relevant ops: 2 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 0 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: NO | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 11965582ns (119ns / call) | # insmod ftrace-ops.ko save_regs=true | ftrace_ops: registering: | relevant ops: 1 | tracee: tracee_relevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | irrelevant ops: 0 | tracee: tracee_irrelevant [ftrace_ops] | tracer: ops_func_nop [ftrace_ops] | saving registers: YES | assist recursion: NO | assist RCU: NO | ftrace_ops: Attempted 100000 calls to tracee_relevant [ftrace_ops] in 4459624ns (44ns / call) Link: https://lkml.kernel.org/r/20230103124912.2948963-4-mark.rutland@arm.com Cc: Florent Revest <revest@chromium.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-01-03 12:49:12 +00:00
obj-$(CONFIG_SAMPLE_FTRACE_OPS) += ftrace-ops.o
tracing: Sample module to demonstrate kernel access to Ftrace instances. This is a sample module to demonstrate the use of the newly introduced and exported APIs to access Ftrace instances from within the kernel. Newly introduced APIs used here - 1. Create/Lookup a trace array with the given name. struct trace_array *trace_array_get_by_name(const char *name) 2. Destroy/Remove a trace array. int trace_array_destroy(struct trace_array *tr) 4. Enable/Disable trace events: int trace_array_set_clr_event(struct trace_array *tr, const char *system, const char *event, bool enable); Exported APIs - 1. trace_printk equivalent for instances. int trace_array_printk(struct trace_array *tr, unsigned long ip, const char *fmt, ...); 2. Helper function. void trace_printk_init_buffers(void); 3. To decrement the reference counter. void trace_array_put(struct trace_array *tr) Sample output(contents of /sys/kernel/tracing/instances/sample-instance) NOTE: Tracing disabled after ~5 sec) _-----=> irqs-off / _----=> need-resched | / _---=> hardirq/softirq || / _--=> preempt-depth ||| / delay TASK-PID CPU# |||| TIMESTAMP FUNCTION | | | |||| | | sample-instance-1452 [002] .... 49.430948: simple_thread: trace_array_printk: count=0 sample-instance-1452 [002] .... 49.430951: sample_event: count value=0 at jiffies=4294716608 sample-instance-1452 [002] .... 50.454847: simple_thread: trace_array_printk: count=1 sample-instance-1452 [002] .... 50.454849: sample_event: count value=1 at jiffies=4294717632 sample-instance-1452 [002] .... 51.478748: simple_thread: trace_array_printk: count=2 sample-instance-1452 [002] .... 51.478750: sample_event: count value=2 at jiffies=4294718656 sample-instance-1452 [002] .... 52.502652: simple_thread: trace_array_printk: count=3 sample-instance-1452 [002] .... 52.502655: sample_event: count value=3 at jiffies=4294719680 sample-instance-1452 [002] .... 53.526533: simple_thread: trace_array_printk: count=4 sample-instance-1452 [002] .... 53.526535: sample_event: count value=4 at jiffies=4294720704 sample-instance-1452 [002] .... 54.550438: simple_thread: trace_array_printk: count=5 sample-instance-1452 [002] .... 55.574336: simple_thread: trace_array_printk: count=6 Link: http://lkml.kernel.org/r/1574276919-11119-3-git-send-email-divya.indi@oracle.com Reviewed-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Signed-off-by: Divya Indi <divya.indi@oracle.com> [ Moved to samples/ftrace ] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-11-20 19:08:39 +00:00
CFLAGS_sample-trace-array.o := -I$(src)
obj-$(CONFIG_SAMPLE_TRACE_ARRAY) += sample-trace-array.o