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perf lock contention: Add --lock-cgroup option

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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: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2023-09-06 10:49:01 -07:00 committed by Arnaldo Carvalho de Melo
parent d0c502e46e
commit 4d1792d0a2
6 changed files with 84 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
tools/perf/Documentation/perf-lock.txt
View File

@ -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
--------

40
tools/perf/builtin-lock.c
View File

@ -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)
};

16
tools/perf/util/bpf_lock_contention.c
View File

@ -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;

31
tools/perf/util/bpf_skel/lock_contention.bpf.c
View File

@ -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;

3
tools/perf/util/bpf_skel/lock_data.h
View File

@ -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 {

1
tools/perf/util/lock-contention.h
View File

@ -144,7 +144,6 @@ struct lock_contention {
int owner;
int nr_filtered;
bool save_callstack;
bool use_cgroup;
};
#ifdef HAVE_BPF_SKEL