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From: Tao Zhou To: Daniel Bristot de Oliveira Cc: Steven Rostedt , Ingo Molnar , Tom Zanussi , Masami Hiramatsu , Juri Lelli , Clark Williams , John Kacur , Peter Zijlstra , Thomas Gleixner , Sebastian Andrzej Siewior , Tao Zhou , linux-rt-users@vger.kernel.org, linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V8 06/14] rtla: Add timerlat tool and timelart top mode Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 29, 2021 at 12:07:44PM +0100, Daniel Bristot de Oliveira wrote: > The rtla timerlat tool is an interface for the timerlat tracer. > The timerlat tracer dispatches a kernel thread per-cpu. These threads set a > periodic timer to wake themselves up and go back to sleep. After the > wakeup, they collect and generate useful information for the debugging of > operating system timer latency. > > The timerlat tracer outputs information in two ways. It periodically > prints the timer latency at the timer IRQ handler and the Thread handler. > It also provides information for each noise via the osnoise tracepoints. > > The rtla timerlat top mode displays a summary of the periodic output from > the timerlat tracer. > > Here is one example of the rtla timerlat tool output: > ---------- %< ---------- > [root@alien ~]# rtla timerlat top -c 0-3 -d 1m > Timer Latency > 0 00:01:00 | IRQ Timer Latency (us) | Thread Timer Latency (us) > CPU COUNT | cur min avg max | cur min avg max > 0 #60001 | 0 0 0 3 | 1 1 1 6 > 1 #60001 | 0 0 0 3 | 2 1 1 5 > 2 #60001 | 0 0 1 6 | 1 1 2 7 > 3 #60001 | 0 0 0 7 | 1 1 1 11 > ---------- >% ---------- > > Running: > # rtla timerlat --help > # rtla timerlat top --help > provides information about the available options. > > Cc: Steven Rostedt > Cc: Ingo Molnar > Cc: Tom Zanussi > Cc: Masami Hiramatsu > Cc: Juri Lelli > Cc: Clark Williams > Cc: John Kacur > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: Sebastian Andrzej Siewior > Cc: Daniel Bristot de Oliveira > Cc: linux-rt-users@vger.kernel.org > Cc: linux-trace-devel@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Daniel Bristot de Oliveira > --- > tools/tracing/rtla/Makefile | 2 + > tools/tracing/rtla/src/rtla.c | 5 + > tools/tracing/rtla/src/timerlat.c | 68 +++ > tools/tracing/rtla/src/timerlat.h | 4 + > tools/tracing/rtla/src/timerlat_top.c | 615 ++++++++++++++++++++++++++ > 5 files changed, 694 insertions(+) > create mode 100644 tools/tracing/rtla/src/timerlat.c > create mode 100644 tools/tracing/rtla/src/timerlat.h > create mode 100644 tools/tracing/rtla/src/timerlat_top.c > > diff --git a/tools/tracing/rtla/Makefile b/tools/tracing/rtla/Makefile > index ba6f327e815a..f254cfbe4fa3 100644 > --- a/tools/tracing/rtla/Makefile > +++ b/tools/tracing/rtla/Makefile > @@ -62,6 +62,8 @@ install: > $(STRIP) $(DESTDIR)$(BINDIR)/rtla > @test ! -f $(DESTDIR)$(BINDIR)/osnoise || rm $(DESTDIR)$(BINDIR)/osnoise > ln -s $(DESTDIR)$(BINDIR)/rtla $(DESTDIR)$(BINDIR)/osnoise > + @test ! -f $(DESTDIR)$(BINDIR)/timerlat || rm $(DESTDIR)$(BINDIR)/timerlat > + ln -s $(DESTDIR)$(BINDIR)/rtla $(DESTDIR)$(BINDIR)/timerlat > > .PHONY: clean tarball > clean: > diff --git a/tools/tracing/rtla/src/rtla.c b/tools/tracing/rtla/src/rtla.c > index 669b9750b3b3..09bd21b8af81 100644 > --- a/tools/tracing/rtla/src/rtla.c > +++ b/tools/tracing/rtla/src/rtla.c > @@ -9,6 +9,7 @@ > #include > > #include "osnoise.h" > +#include "timerlat.h" > > /* > * rtla_usage - print rtla usage > @@ -25,6 +26,7 @@ static void rtla_usage(void) > "", > " commands:", > " osnoise - gives information about the operating system noise (osnoise)", > + " timerlat - measures the timer irq and thread latency", > "", > NULL, > }; > @@ -45,6 +47,9 @@ int run_command(int argc, char **argv, int start_position) > if (strcmp(argv[start_position], "osnoise") == 0) { > osnoise_main(argc-start_position, &argv[start_position]); > goto ran; > + } else if (strcmp(argv[start_position], "timerlat") == 0) { > + timerlat_main(argc-start_position, &argv[start_position]); > + goto ran; > } > > return 0; > diff --git a/tools/tracing/rtla/src/timerlat.c b/tools/tracing/rtla/src/timerlat.c > new file mode 100644 > index 000000000000..29a51c01b084 > --- /dev/null > +++ b/tools/tracing/rtla/src/timerlat.c > @@ -0,0 +1,68 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira > + */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "timerlat.h" > + > +static void timerlat_usage(void) > +{ > + int i; > + > + static const char * const msg[] = { > + "", > + "timerlat version " VERSION, > + "", > + " usage: [rtla] timerlat [MODE] ...", > + "", > + " modes:", > + " top - prints the summary from timerlat tracer", > + "", > + "if no MODE is given, the top mode is called, passing the arguments", > + NULL, > + }; > + > + for (i = 0; msg[i]; i++) > + fprintf(stderr, "%s\n", msg[i]); > + exit(1); > +} > + > +int timerlat_main(int argc, char *argv[]) > +{ > + if (argc == 0) > + goto usage; > + > + /* > + * if timerlat was called without any argument, run the > + * default cmdline. > + */ > + if (argc == 1) { > + timerlat_top_main(argc, argv); > + exit(0); > + } > + > + if ((strcmp(argv[1], "-h") == 0) || (strcmp(argv[1], "--help") == 0)) { > + timerlat_usage(); > + exit(0); > + } else if (strncmp(argv[1], "-", 1) == 0) { > + /* the user skipped the tool, call the default one */ > + timerlat_top_main(argc, argv); > + exit(0); > + } else if (strcmp(argv[1], "top") == 0) { > + timerlat_top_main(argc-1, &argv[1]); > + exit(0); > + } > + > +usage: > + timerlat_usage(); > + exit(1); > +} > diff --git a/tools/tracing/rtla/src/timerlat.h b/tools/tracing/rtla/src/timerlat.h > new file mode 100644 > index 000000000000..6f9d3925acd0 > --- /dev/null > +++ b/tools/tracing/rtla/src/timerlat.h > @@ -0,0 +1,4 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +int timerlat_top_main(int argc, char *argv[]); > +int timerlat_main(int argc, char *argv[]); > diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c > new file mode 100644 > index 000000000000..9764681ad8b1 > --- /dev/null > +++ b/tools/tracing/rtla/src/timerlat_top.c > @@ -0,0 +1,615 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2021 Red Hat Inc, Daniel Bristot de Oliveira > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "utils.h" > +#include "osnoise.h" > +#include "timerlat.h" > + > +struct timerlat_top_params { > + char *cpus; > + char *monitored_cpus; > + char *trace_output; > + unsigned long long runtime; > + long long stop_us; > + long long stop_total_us; > + long long timerlat_period_us; > + long long print_stack; > + int sleep_time; > + int output_divisor; > + int duration; > + int quiet; > + int set_sched; > + struct sched_attr sched_param; > +}; > + > +struct timerlat_top_cpu { > + int irq_count; > + int thread_count; > + > + unsigned long long cur_irq; > + unsigned long long min_irq; > + unsigned long long sum_irq; > + unsigned long long max_irq; > + > + unsigned long long cur_thread; > + unsigned long long min_thread; > + unsigned long long sum_thread; > + unsigned long long max_thread; > +}; > + > +struct timerlat_top_data { > + struct timerlat_top_cpu *cpu_data; > + int nr_cpus; > +}; > + > +/* > + * timerlat_free_top - free runtime data > + */ > +static void > +timerlat_free_top(struct timerlat_top_data *data) > +{ > + free(data->cpu_data); > + free(data); > +} > + > +/* > + * timerlat_alloc_histogram - alloc runtime data > + */ > +static struct timerlat_top_data *timerlat_alloc_top(int nr_cpus) > +{ > + struct timerlat_top_data *data; > + int cpu; > + > + data = calloc(1, sizeof(*data)); > + if (!data) > + return NULL; > + > + data->nr_cpus = nr_cpus; > + > + /* one set of histograms per CPU */ > + data->cpu_data = calloc(1, sizeof(*data->cpu_data) * nr_cpus); > + if (!data->cpu_data) > + goto cleanup; > + > + /* set the min to max */ > + for (cpu = 0; cpu < nr_cpus; cpu++) { > + data->cpu_data[cpu].min_irq = ~0; > + data->cpu_data[cpu].min_thread = ~0; > + } > + > + return data; > + > +cleanup: > + timerlat_free_top(data); > + return NULL; > +} > + > +/* > + * timerlat_hist_update - record a new timerlat occurent on cpu, updating data > + */ > +static void > +timerlat_top_update(struct osnoise_tool *tool, int cpu, > + unsigned long long thread, > + unsigned long long latency) > +{ > + struct timerlat_top_data *data = tool->data; > + struct timerlat_top_cpu *cpu_data = &data->cpu_data[cpu]; > + > + if (!thread) { > + cpu_data->irq_count++; > + cpu_data->cur_irq = latency; > + update_min(&cpu_data->min_irq, &latency); > + update_sum(&cpu_data->sum_irq, &latency); > + update_max(&cpu_data->max_irq, &latency); > + } else { > + cpu_data->thread_count++; > + cpu_data->cur_thread = latency; > + update_min(&cpu_data->min_thread, &latency); > + update_sum(&cpu_data->sum_thread, &latency); > + update_max(&cpu_data->max_thread, &latency); > + } > +} > + > +/* > + * timerlat_top_handler - this is the handler for timerlat tracer events > + */ > +static int > +timerlat_top_handler(struct trace_seq *s, struct tep_record *record, > + struct tep_event *event, void *context) > +{ > + struct trace_instance *trace = context; > + unsigned long long latency, thread; > + struct osnoise_tool *top; > + int cpu = record->cpu; > + > + top = container_of(trace, struct osnoise_tool, trace); > + > + tep_get_field_val(s, event, "context", record, &thread, 1); > + tep_get_field_val(s, event, "timer_latency", record, &latency, 1); > + > + timerlat_top_update(top, cpu, thread, latency); > + > + return 0; > +} > + > +/* > + * timerlat_top_header - print the header of the tool output > + */ > +static void timerlat_top_header(struct osnoise_tool *top) > +{ > + struct timerlat_top_params *params = top->params; > + struct trace_seq *s = top->trace.seq; > + char duration[26]; > + > + get_duration(top->start_time, duration, sizeof(duration)); > + > + trace_seq_printf(s, "\033[2;37;40m"); > + trace_seq_printf(s, " Timer Latency "); > + trace_seq_printf(s, "\033[0;0;0m"); > + trace_seq_printf(s, "\n"); > + > + trace_seq_printf(s, "%-6s | IRQ Timer Latency (%s) | Thread Timer Latency (%s)\n", duration, > + params->output_divisor == 1 ? "ns" : "us", > + params->output_divisor == 1 ? "ns" : "us"); > + > + trace_seq_printf(s, "\033[2;30;47m"); > + trace_seq_printf(s, "CPU COUNT | cur min avg max | cur min avg max"); > + trace_seq_printf(s, "\033[0;0;0m"); > + trace_seq_printf(s, "\n"); > +} > + > +/* > + * timerlat_top_print - prints the output of a given CPU > + */ > +static void timerlat_top_print(struct osnoise_tool *top, int cpu) > +{ > + > + struct timerlat_top_params *params = top->params; > + struct timerlat_top_data *data = top->data; > + struct timerlat_top_cpu *cpu_data = &data->cpu_data[cpu]; > + int divisor = params->output_divisor; > + struct trace_seq *s = top->trace.seq; > + > + if (divisor == 0) > + return; > + > + /* > + * Skip if no data is available: is this cpu offline? > + */ > + if (!cpu_data->irq_count && !cpu_data->thread_count) > + return; > + > + /* > + * Unless trace is being lost, IRQ counter is always the max. > + */ > + trace_seq_printf(s, "%3d #%-9d |", cpu, cpu_data->irq_count); > + > + if (!cpu_data->irq_count) { > + trace_seq_printf(s, " - "); > + trace_seq_printf(s, " - "); > + trace_seq_printf(s, " - "); > + trace_seq_printf(s, " - |"); > + } else { > + trace_seq_printf(s, "%9llu ", cpu_data->cur_irq / params->output_divisor); > + trace_seq_printf(s, "%9llu ", cpu_data->min_irq / params->output_divisor); > + trace_seq_printf(s, "%9llu ", (cpu_data->sum_irq / cpu_data->irq_count) / divisor); > + trace_seq_printf(s, "%9llu |", cpu_data->max_irq / divisor); > + } > + > + if (!cpu_data->thread_count) { > + trace_seq_printf(s, " - "); > + trace_seq_printf(s, " - "); > + trace_seq_printf(s, " - "); > + trace_seq_printf(s, " -\n"); > + } else { > + trace_seq_printf(s, "%9llu ", cpu_data->cur_thread / divisor); > + trace_seq_printf(s, "%9llu ", cpu_data->min_thread / divisor); > + trace_seq_printf(s, "%9llu ", > + (cpu_data->sum_thread / cpu_data->thread_count) / divisor); > + trace_seq_printf(s, "%9llu\n", cpu_data->max_thread / divisor); > + } > +} > + > +/* > + * clear_terminal - clears the output terminal > + */ > +static void clear_terminal(struct trace_seq *seq) > +{ > + if (!config_debug) > + trace_seq_printf(seq, "\033c"); > +} > + > +/* > + * timerlat_print_stats - print data for all cpus > + */ > +static void > +timerlat_print_stats(struct timerlat_top_params *params, struct osnoise_tool *top) > +{ > + struct trace_instance *trace = &top->trace; > + static int nr_cpus = -1; > + int i; > + > + if (nr_cpus == -1) > + nr_cpus = sysconf(_SC_NPROCESSORS_CONF); > + > + if (!params->quiet) > + clear_terminal(trace->seq); > + > + timerlat_top_header(top); > + > + for (i = 0; i < nr_cpus; i++) { > + if (params->cpus && !params->monitored_cpus[i]) > + continue; > + timerlat_top_print(top, i); > + } > + > + trace_seq_do_printf(trace->seq); > + trace_seq_reset(trace->seq); > +} > + > +/* > + * timerlat_top_usage - prints timerlat top usage message > + */ > +static void timerlat_top_usage(char *usage) > +{ > + int i; > + > + static const char *const msg[] = { > + "", > + " usage: rtla timerlat [top] [-h] [-q] [-p us] [-i us] [-t us] [-s us] [-T[=file]] \\", > + " [-c cpu-list] [-P priority]", > + "", > + " -h/--help: print this menu", > + " -p/--period us: timerlat period in us", > + " -i/--irq us: stop trace if the irq latency is higher than the argument in us", > + " -T/--thread us: stop trace if the thread latency is higher than the argument in us", > + " -s/--stack us: save the stack trace at the IRQ if a thread latency is higher than the argument in us", > + " -c/--cpus cpus: run the tracer only on the given cpus -d/--duration time[m|h|d]: duration of the session in seconds", > + " -t/--trace[=file]: save the stopped trace to [file|timerlat_trace.txt]", > + " -n/--nano: display data in nanoseconds", > + " -q/--quiet print only a summary at the end", > + " -P/--priority o:prio|r:prio|f:prio|d:runtime:period : set scheduling parameters", > + " o:prio - use SCHED_OTHER with prio", > + " r:prio - use SCHED_RR with prio", > + " f:prio - use SCHED_FIFO with prio", > + " d:runtime[us|ms|s]:period[us|ms|s] - use SCHED_DEADLINE with runtime and period", > + " in nanoseconds", > + NULL, > + }; About help usage msg. [-t us] --> [-T us] [-T=[file]] --> [-t[=file]] [-d] [-D] [-n] lack in the head usage info 'usage: ...' > + > + if (usage) > + fprintf(stderr, "%s\n", usage); > + > + fprintf(stderr, "rtla timerlat top: a per-cpu summary of the timer latency (version %s)\n", > + VERSION); > + > + for (i = 0; msg[i]; i++) > + fprintf(stderr, "%s\n", msg[i]); > + exit(1); > +} > +