Re: [PATCH] perf script: Add 'cgroup' field for output

[Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>]

On January 26, 2023 4:42:30 PM GMT-03:00, Namhyung Kim <namhyung@kernel.org> wrote:
>There's no field for the cgroup, let's add one.  To do that, users need to
>specify --all-cgroup option for perf record to capture the cgroup info.


This information about the new field being only available when --all-cgroup is specified should be in the documentation (man page) and probably in the tool itself, refusing it when the needed command line isn't present.

- Arnaldo 

>
>  $ perf record --all-cgroups -- true
>
>  $ perf script -F comm,pid,cgroup
>            true 337112  /user.slice/user-657345.slice/user@657345.service/...
>            true 337112  /user.slice/user-657345.slice/user@657345.service/...
>            true 337112  /user.slice/user-657345.slice/user@657345.service/...
>            true 337112  /user.slice/user-657345.slice/user@657345.service/...
>
>Signed-off-by: Namhyung Kim <namhyung@kernel.org>
>---
> tools/perf/Documentation/perf-script.txt |  2 +-
> tools/perf/builtin-script.c              | 16 +++++++++++++++-
> 2 files changed, 16 insertions(+), 2 deletions(-)
>
>diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
>index 8d77182fbf31..82c4dcb9c42e 100644
>--- a/tools/perf/Documentation/perf-script.txt
>+++ b/tools/perf/Documentation/perf-script.txt
>@@ -134,7 +134,7 @@ OPTIONS
>         srcline, period, iregs, uregs, brstack, brstacksym, flags, bpf-output,
>         brstackinsn, brstackinsnlen, brstackoff, callindent, insn, insnlen, synth,
>         phys_addr, metric, misc, srccode, ipc, data_page_size, code_page_size, ins_lat,
>-        machine_pid, vcpu.
>+        machine_pid, vcpu, cgroup.
>         Field list can be prepended with the type, trace, sw or hw,
>         to indicate to which event type the field list applies.
>         e.g., -F sw:comm,tid,time,ip,sym  and -F trace:time,cpu,trace
>diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
>index 69394ac0a20d..79976dde99b3 100644
>--- a/tools/perf/builtin-script.c
>+++ b/tools/perf/builtin-script.c
>@@ -59,6 +59,7 @@
> #include "util/dlfilter.h"
> #include "util/record.h"
> #include "util/util.h"
>+#include "util/cgroup.h"
> #include "perf.h"
> 
> #include <linux/ctype.h>
>@@ -130,6 +131,7 @@ enum perf_output_field {
> 	PERF_OUTPUT_BRSTACKINSNLEN  = 1ULL << 36,
> 	PERF_OUTPUT_MACHINE_PID     = 1ULL << 37,
> 	PERF_OUTPUT_VCPU            = 1ULL << 38,
>+	PERF_OUTPUT_CGROUP          = 1ULL << 39,
> };
> 
> struct perf_script {
>@@ -200,6 +202,7 @@ struct output_option {
> 	{.str = "brstackinsnlen", .field = PERF_OUTPUT_BRSTACKINSNLEN},
> 	{.str = "machine_pid", .field = PERF_OUTPUT_MACHINE_PID},
> 	{.str = "vcpu", .field = PERF_OUTPUT_VCPU},
>+	{.str = "cgroup", .field = PERF_OUTPUT_CGROUP},
> };
> 
> enum {
>@@ -2220,6 +2223,17 @@ static void process_event(struct perf_script *script,
> 	if (PRINT_FIELD(CODE_PAGE_SIZE))
> 		fprintf(fp, " %s", get_page_size_name(sample->code_page_size, str));
> 
>+	if (PRINT_FIELD(CGROUP)) {
>+		const char *cgrp_name;
>+		struct cgroup *cgrp = cgroup__find(machine->env,
>+						   sample->cgroup);
>+		if (cgrp != NULL)
>+			cgrp_name = cgrp->name;
>+		else
>+			cgrp_name = "unknown";
>+		fprintf(fp, " %s", cgrp_name);
>+	}
>+
> 	perf_sample__fprintf_ipc(sample, attr, fp);
> 
> 	fprintf(fp, "\n");
>@@ -3856,7 +3870,7 @@ int cmd_script(int argc, const char **argv)
> 		     "brstacksym,flags,data_src,weight,bpf-output,brstackinsn,"
> 		     "brstackinsnlen,brstackoff,callindent,insn,insnlen,synth,"
> 		     "phys_addr,metric,misc,srccode,ipc,tod,data_page_size,"
>-		     "code_page_size,ins_lat",
>+		     "code_page_size,ins_lat,machine_pid,vcpu,cgroup",
> 		     parse_output_fields),
> 	OPT_BOOLEAN('a', "all-cpus", &system_wide,
> 		    "system-wide collection from all CPUs"),