Re: [PATCH 3/5] perf lock contention: Add -g/--lock-cgroup option
From: Arnaldo Carvalho de Melo
Date: Wed Sep 06 2023 - 15:29:22 EST
Em Wed, Sep 06, 2023 at 04:23:17PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Wed, Sep 06, 2023 at 10:49:01AM -0700, Namhyung Kim escreveu:
> > The -g 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 -abg 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).
>
> Can we try to be consistent with other tools?
>
> [root@quaco ~]# perf record -h -g
>
> Usage: perf record [<options>] [<command>]
> or: perf record [<options>] -- <command> [<options>]
>
> -g enables call-graph recording
>
> [root@quaco ~]# perf record -h -G
>
> Usage: perf record [<options>] [<command>]
> or: perf record [<options>] -- <command> [<options>]
>
> -G, --cgroup <name> monitor event in cgroup name only
>
> [root@quaco ~]# set -o vi
> [root@quaco ~]# perf lock contention -h -G
>
> Usage: perf lock contention [<options>]
>
>
> [root@quaco ~]#
>
> I.e. use -G in this patch?
>
> If you agree I can fixup things here, otherwise why not?
I see that you use -G in 4/5, unsure now, but this looks like --sort in
'perf report', no?
- Arnaldo
> - Arnaldo
>
> > Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > ---
> > tools/perf/Documentation/perf-lock.txt | 4 ++
> > tools/perf/builtin-lock.c | 40 ++++++++++++++++++-
> > tools/perf/util/bpf_lock_contention.c | 16 +++++---
> > .../perf/util/bpf_skel/lock_contention.bpf.c | 31 +++++++++++++-
> > tools/perf/util/bpf_skel/lock_data.h | 3 +-
> > tools/perf/util/lock-contention.h | 1 -
> > 6 files changed, 85 insertions(+), 10 deletions(-)
> >
> > diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
> > index 30eea576721f..61c491df72b8 100644
> > --- a/tools/perf/Documentation/perf-lock.txt
> > +++ b/tools/perf/Documentation/perf-lock.txt
> > @@ -208,6 +208,10 @@ 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.
> >
> > +-g::
> > +--lock-cgroup::
> > + Show lock contention stat by cgroup. Requires --use-bpf.
> > +
> >
> > SEE ALSO
> > --------
> > diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> > index 06430980dfd7..b98948dd40ba 100644
> > --- a/tools/perf/builtin-lock.c
> > +++ b/tools/perf/builtin-lock.c
> > @@ -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('g', "lock-cgroup", &show_lock_cgroups, "show lock stats by cgroup"),
> > OPT_PARENT(lock_options)
> > };
> >
> > diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
> > index c6bd7c9b2d57..42753a0dfdc5 100644
> > --- a/tools/perf/util/bpf_lock_contention.c
> > +++ b/tools/perf/util/bpf_lock_contention.c
> > @@ -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;
> > diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
> > index 8d3cfbb3cc65..823354999022 100644
> > --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
> > +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
> > @@ -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;
> > diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h
> > index 260062a9f2ab..08482daf61be 100644
> > --- a/tools/perf/util/bpf_skel/lock_data.h
> > +++ b/tools/perf/util/bpf_skel/lock_data.h
> > @@ -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 {
> > diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h
> > index 70423966d778..a073cc6a82d2 100644
> > --- a/tools/perf/util/lock-contention.h
> > +++ b/tools/perf/util/lock-contention.h
> > @@ -144,7 +144,6 @@ struct lock_contention {
> > int owner;
> > int nr_filtered;
> > bool save_callstack;
> > - bool use_cgroup;
> > };
> >
> > #ifdef HAVE_BPF_SKEL
> > --
> > 2.42.0.283.g2d96d420d3-goog
> >
>
> --
>
> - Arnaldo
--
- Arnaldo