Commit 4d1792d0 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
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perf lock contention: Add --lock-cgroup option 



The --lock-cgroup option shows lock contention stats break down by
cgroups.

Add LOCK_AGGR_CGROUP mode and use it instead of use_cgroup field.

  $ sudo ./perf lock con -ab --lock-cgroup sleep 1
   contended   total wait     max wait     avg wait   cgroup

           8     15.70 us      6.34 us      1.96 us   /
           2      1.48 us       747 ns       738 ns   /user.slice/.../app.slice/app-gnome-google\x2dchrome-6442.scope
           1       848 ns       848 ns       848 ns   /user.slice/.../session.slice/org.gnome.Shell@x11.service
           1       220 ns       220 ns       220 ns   /user.slice/.../session.slice/pipewire-pulse.service

For now, the cgroup mode only works with BPF (-b).

Committer notes:

Remove -g as it is used in the other tools with a clear meaning of
collect/show callchains. As agreed with Namhyung off list.

Reviewed-by: default avatarIan Rogers <irogers@google.com>
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230906174903.346486-4-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d0c502e4

tools/perf/Documentation/perf-lock.txt

+3 −0
Original line number Diff line number Diff line
@@ -208,6 +208,9 @@ CONTENTION OPTIONS 
	Show results using a CSV-style output to make it easy to import directly

	into spreadsheets. Columns are separated by the string specified in SEP.



--lock-cgroup::

	Show lock contention stat by cgroup.  Requires --use-bpf.





SEE ALSO

--------

tools/perf/builtin-lock.c

+39 −1
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ static bool combine_locks; 
static bool show_thread_stats;

static bool show_lock_addrs;

static bool show_lock_owner;

static bool show_lock_cgroups;

static bool use_bpf;

static unsigned long bpf_map_entries = MAX_ENTRIES;

static int max_stack_depth = CONTENTION_STACK_DEPTH;
@@ -619,6 +620,7 @@ static int get_key_by_aggr_mode_simple(u64 *key, u64 addr, u32 tid) 
		*key = tid;

		break;

	case LOCK_AGGR_CALLER:

	case LOCK_AGGR_CGROUP:

	default:

		pr_err("Invalid aggregation mode: %d\n", aggr_mode);

		return -EINVAL;
@@ -1103,6 +1105,7 @@ static int report_lock_contention_begin_event(struct evsel *evsel, 
			if (lock_contention_caller(evsel, sample, buf, sizeof(buf)) < 0)

				name = "Unknown";

			break;

		case LOCK_AGGR_CGROUP:

		case LOCK_AGGR_TASK:

		default:

			break;
@@ -1653,6 +1656,9 @@ static void print_header_stdio(void) 
	case LOCK_AGGR_ADDR:

		fprintf(lock_output, "  %16s   %s\n\n", "address", "symbol");

		break;

	case LOCK_AGGR_CGROUP:

		fprintf(lock_output, "  %s\n\n", "cgroup");

		break;

	default:

		break;

	}
@@ -1680,6 +1686,9 @@ static void print_header_csv(const char *sep) 
	case LOCK_AGGR_ADDR:

		fprintf(lock_output, "%s%s %s%s %s\n", "address", sep, "symbol", sep, "type");

		break;

	case LOCK_AGGR_CGROUP:

		fprintf(lock_output, "%s\n", "cgroup");

		break;

	default:

		break;

	}
@@ -1720,6 +1729,9 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat 
		fprintf(lock_output, "  %016llx   %s (%s)\n", (unsigned long long)st->addr,

			st->name, get_type_name(st->flags));

		break;

	case LOCK_AGGR_CGROUP:

		fprintf(lock_output, "  %s\n", st->name);

		break;

	default:

		break;

	}
@@ -1770,6 +1782,9 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s 
		fprintf(lock_output, "%llx%s %s%s %s\n", (unsigned long long)st->addr, sep,

			st->name, sep, get_type_name(st->flags));

		break;

	case LOCK_AGGR_CGROUP:

		fprintf(lock_output, "%s\n",st->name);

		break;

	default:

		break;

	}
@@ -1999,6 +2014,27 @@ static int check_lock_contention_options(const struct option *options, 
		return -1;

	}



	if (show_lock_cgroups && !use_bpf) {

		pr_err("Cgroups are available only with BPF\n");

		parse_options_usage(usage, options, "lock-cgroup", 0);

		parse_options_usage(NULL, options, "use-bpf", 0);

		return -1;

	}



	if (show_lock_cgroups && show_lock_addrs) {

		pr_err("Cannot use cgroup and addr mode together\n");

		parse_options_usage(usage, options, "lock-cgroup", 0);

		parse_options_usage(NULL, options, "lock-addr", 0);

		return -1;

	}



	if (show_lock_cgroups && show_thread_stats) {

		pr_err("Cannot use cgroup and thread mode together\n");

		parse_options_usage(usage, options, "lock-cgroup", 0);

		parse_options_usage(NULL, options, "threads", 0);

		return -1;

	}



	if (symbol_conf.field_sep) {

		if (strstr(symbol_conf.field_sep, ":") || /* part of type flags */

		    strstr(symbol_conf.field_sep, "+") || /* part of caller offset */
@@ -2060,7 +2096,8 @@ static int __cmd_contention(int argc, const char **argv) 
	con.machine = &session->machines.host;



	con.aggr_mode = aggr_mode = show_thread_stats ? LOCK_AGGR_TASK :

		show_lock_addrs ? LOCK_AGGR_ADDR : LOCK_AGGR_CALLER;

		show_lock_addrs ? LOCK_AGGR_ADDR :

		show_lock_cgroups ? LOCK_AGGR_CGROUP : LOCK_AGGR_CALLER;



	if (con.aggr_mode == LOCK_AGGR_CALLER)

		con.save_callstack = true;
@@ -2524,6 +2561,7 @@ int cmd_lock(int argc, const char **argv) 
	OPT_BOOLEAN('o', "lock-owner", &show_lock_owner, "show lock owners instead of waiters"),

	OPT_STRING_NOEMPTY('x', "field-separator", &symbol_conf.field_sep, "separator",

		   "print result in CSV format with custom separator"),

	OPT_BOOLEAN(0, "lock-cgroup", &show_lock_cgroups, "show lock stats by cgroup"),

	OPT_PARENT(lock_options)

	};

tools/perf/util/bpf_lock_contention.c

+10 −6
Original line number Diff line number Diff line
@@ -152,7 +152,10 @@ int lock_contention_prepare(struct lock_contention *con) 
	skel->bss->needs_callstack = con->save_callstack;

	skel->bss->lock_owner = con->owner;



	if (con->use_cgroup) {

	if (con->aggr_mode == LOCK_AGGR_CGROUP) {

		if (cgroup_is_v2("perf_event"))

			skel->bss->use_cgroup_v2 = 1;



		read_all_cgroups(&con->cgroups);

	}
@@ -214,12 +217,12 @@ static const char *lock_contention_get_name(struct lock_contention *con, 
			return "siglock";



		/* global locks with symbols */

		sym = machine__find_kernel_symbol(machine, key->lock_addr, &kmap);

		sym = machine__find_kernel_symbol(machine, key->lock_addr_or_cgroup, &kmap);

		if (sym)

			return sym->name;



		/* try semi-global locks collected separately */

		if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr, &flags)) {

		if (!bpf_map_lookup_elem(lock_fd, &key->lock_addr_or_cgroup, &flags)) {

			if (flags == LOCK_CLASS_RQLOCK)

				return "rq_lock";

		}
@@ -227,8 +230,8 @@ static const char *lock_contention_get_name(struct lock_contention *con, 
		return "";

	}



	if (con->use_cgroup) {

		u64 cgrp_id = key->lock_addr;

	if (con->aggr_mode == LOCK_AGGR_CGROUP) {

		u64 cgrp_id = key->lock_addr_or_cgroup;

		struct cgroup *cgrp = __cgroup__find(&con->cgroups, cgrp_id);



		if (cgrp)
@@ -329,7 +332,8 @@ int lock_contention_read(struct lock_contention *con) 
			ls_key = key.pid;

			break;

		case LOCK_AGGR_ADDR:

			ls_key = key.lock_addr;

		case LOCK_AGGR_CGROUP:

			ls_key = key.lock_addr_or_cgroup;

			break;

		default:

			goto next;

tools/perf/util/bpf_skel/lock_contention.bpf.c

+30 −1
Original line number Diff line number Diff line
@@ -118,6 +118,9 @@ int needs_callstack; 
int stack_skip;

int lock_owner;



int use_cgroup_v2;

int perf_subsys_id = -1;



/* determine the key of lock stat */

int aggr_mode;
@@ -130,6 +133,29 @@ int data_fail; 
int task_map_full;

int data_map_full;



static inline __u64 get_current_cgroup_id(void)

{

	struct task_struct *task;

	struct cgroup *cgrp;



	if (use_cgroup_v2)

		return bpf_get_current_cgroup_id();



	task = bpf_get_current_task_btf();



	if (perf_subsys_id == -1) {

#if __has_builtin(__builtin_preserve_enum_value)

		perf_subsys_id = bpf_core_enum_value(enum cgroup_subsys_id,

						     perf_event_cgrp_id);

#else

		perf_subsys_id = perf_event_cgrp_id;

#endif

	}



	cgrp = BPF_CORE_READ(task, cgroups, subsys[perf_subsys_id], cgroup);

	return BPF_CORE_READ(cgrp, kn, id);

}



static inline int can_record(u64 *ctx)

{

	if (has_cpu) {
@@ -364,10 +390,13 @@ int contention_end(u64 *ctx) 
			key.stack_id = pelem->stack_id;

		break;

	case LOCK_AGGR_ADDR:

		key.lock_addr = pelem->lock;

		key.lock_addr_or_cgroup = pelem->lock;

		if (needs_callstack)

			key.stack_id = pelem->stack_id;

		break;

	case LOCK_AGGR_CGROUP:

		key.lock_addr_or_cgroup = get_current_cgroup_id();

		break;

	default:

		/* should not happen */

		return 0;

tools/perf/util/bpf_skel/lock_data.h

+2 −1
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ 
struct contention_key {

	u32 stack_id;

	u32 pid;

	u64 lock_addr;

	u64 lock_addr_or_cgroup;

};



#define TASK_COMM_LEN  16
@@ -39,6 +39,7 @@ enum lock_aggr_mode { 
	LOCK_AGGR_ADDR = 0,

	LOCK_AGGR_TASK,

	LOCK_AGGR_CALLER,

	LOCK_AGGR_CGROUP,

};



enum lock_class_sym {