lkml.org 
[lkml]   [2022]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [RFC v3 01/17] perf kwork: New tool
Hello,

On Fri, Jul 8, 2022 at 6:53 PM Yang Jihong <yangjihong1@huawei.com> wrote:
>
> The perf-kwork tool is used to trace time properties of kernel work
> (such as irq, softirq, and workqueue), including runtime, latency,
> and timehist, using the infrastructure in the perf tools to allow
> tracing extra targets.
>
> This is the first commit to reuse perf_record framework code to
> implement a simple record function, kwork is not supported currently.
>
> Test cases:
>
> # perf
>
> usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS]
>
> The most commonly used perf commands are:
> <SNIP>
> iostat Show I/O performance metrics
> kallsyms Searches running kernel for symbols
> kmem Tool to trace/measure kernel memory properties
> kvm Tool to trace/measure kvm guest os
> kwork Tool to trace/measure kernel work properties (latencies)
> list List all symbolic event types
> lock Analyze lock events
> mem Profile memory accesses
> record Run a command and record its profile into perf.data
> <SNIP>
> See 'perf help COMMAND' for more information on a specific command.
>
> # perf kwork
>
> Usage: perf kwork [<options>] {record}
>
> -D, --dump-raw-trace dump raw trace in ASCII
> -f, --force don't complain, do it
> -k, --kwork <kwork> list of kwork to profile
> -v, --verbose be more verbose (show symbol address, etc)
>
> # perf kwork record -- sleep 1
> [ perf record: Woken up 0 times to write data ]
> [ perf record: Captured and wrote 1.787 MB perf.data ]
>
> Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
> ---
[SNIP]
> +
> +static int perf_kwork__record(struct perf_kwork *kwork,
> + int argc, const char **argv)
> +{
> + const char **rec_argv;
> + unsigned int rec_argc, i, j;
> + struct kwork_class *class;
> +
> + const char *const record_args[] = {
> + "record",
> + "-a",
> + "-R",
> + "-m", "1024",
> + "-c", "1",

Please consider adding '--synth task' to skip costly synthesis
if you don't need user space symbols.

> + };
> +
> + rec_argc = ARRAY_SIZE(record_args) + argc - 1;
> +
> + list_for_each_entry(class, &kwork->class_list, list)
> + rec_argc += 2 * class->nr_tracepoints;
> +
> + rec_argv = calloc(rec_argc + 1, sizeof(char *));
> + if (rec_argv == NULL)
> + return -ENOMEM;
> +
> + for (i = 0; i < ARRAY_SIZE(record_args); i++)
> + rec_argv[i] = strdup(record_args[i]);
> +
> + list_for_each_entry(class, &kwork->class_list, list) {
> + for (j = 0; j < class->nr_tracepoints; j++) {
> + rec_argv[i++] = strdup("-e");
> + rec_argv[i++] = strdup(class->tp_handlers[j].name);
> + }
> + }
> +
> + for (j = 1; j < (unsigned int)argc; j++, i++)
> + rec_argv[i] = argv[j];
> +
> + BUG_ON(i != rec_argc);
> +
> + pr_debug("record comm: ");
> + for (j = 0; j < rec_argc; j++)
> + pr_debug("%s ", rec_argv[j]);
> + pr_debug("\n");
> +
> + return cmd_record(i, rec_argv);
> +}

\
 
 \ /
  Last update: 2022-07-28 01:34    [W:0.212 / U:2.280 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site