diff mbox series

[3/6] perf record: Implement basic filtering for off-cpu

Message ID 20220518224725.742882-4-namhyung@kernel.org (mailing list archive)
State RFC
Delegated to: BPF
Headers show
Series perf record: Implement off-cpu profiling with BPF (v3) | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-VM_Test-2 success Logs for Kernel LATEST on ubuntu-latest with llvm-15
bpf/vmtest-bpf-next-VM_Test-3 fail Logs for Kernel LATEST on z15 with gcc
bpf/vmtest-bpf-next-PR fail PR summary
bpf/vmtest-bpf-next-VM_Test-1 success Logs for Kernel LATEST on ubuntu-latest with gcc
netdev/tree_selection success Not a local patch

Commit Message

Namhyung Kim May 18, 2022, 10:47 p.m. UTC
It should honor cpu and task filtering with -a, -C or -p, -t options.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-record.c            |  2 +-
 tools/perf/util/bpf_off_cpu.c          | 78 +++++++++++++++++++++++---
 tools/perf/util/bpf_skel/off_cpu.bpf.c | 52 +++++++++++++++--
 tools/perf/util/off_cpu.h              |  6 +-
 4 files changed, 123 insertions(+), 15 deletions(-)

Comments

Ian Rogers May 19, 2022, 4:02 a.m. UTC | #1
On Wed, May 18, 2022 at 3:47 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> It should honor cpu and task filtering with -a, -C or -p, -t options.
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  tools/perf/builtin-record.c            |  2 +-
>  tools/perf/util/bpf_off_cpu.c          | 78 +++++++++++++++++++++++---
>  tools/perf/util/bpf_skel/off_cpu.bpf.c | 52 +++++++++++++++--
>  tools/perf/util/off_cpu.h              |  6 +-
>  4 files changed, 123 insertions(+), 15 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 91f88501412e..7f60d2eac0b4 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -907,7 +907,7 @@ static int record__config_text_poke(struct evlist *evlist)
>
>  static int record__config_off_cpu(struct record *rec)
>  {
> -       return off_cpu_prepare(rec->evlist);
> +       return off_cpu_prepare(rec->evlist, &rec->opts.target);
>  }
>
>  static bool record__kcore_readable(struct machine *machine)
> diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
> index 9ed7aca3f4ac..b5e2d038da50 100644
> --- a/tools/perf/util/bpf_off_cpu.c
> +++ b/tools/perf/util/bpf_off_cpu.c
> @@ -6,6 +6,9 @@
>  #include "util/off_cpu.h"
>  #include "util/perf-hooks.h"
>  #include "util/session.h"
> +#include "util/target.h"
> +#include "util/cpumap.h"
> +#include "util/thread_map.h"
>  #include <bpf/bpf.h>
>
>  #include "bpf_skel/off_cpu.skel.h"
> @@ -60,8 +63,23 @@ static int off_cpu_config(struct evlist *evlist)
>         return 0;
>  }
>
> -static void off_cpu_start(void *arg __maybe_unused)
> +static void off_cpu_start(void *arg)
>  {
> +       struct evlist *evlist = arg;
> +
> +       /* update task filter for the given workload */
> +       if (!skel->bss->has_cpu && !skel->bss->has_task &&
> +           perf_thread_map__pid(evlist->core.threads, 0) != -1) {
> +               int fd;
> +               u32 pid;
> +               u8 val = 1;
> +
> +               skel->bss->has_task = 1;
> +               fd = bpf_map__fd(skel->maps.task_filter);
> +               pid = perf_thread_map__pid(evlist->core.threads, 0);
> +               bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
> +       }
> +
>         skel->bss->enabled = 1;
>  }
>
> @@ -71,31 +89,75 @@ static void off_cpu_finish(void *arg __maybe_unused)
>         off_cpu_bpf__destroy(skel);
>  }
>
> -int off_cpu_prepare(struct evlist *evlist)
> +int off_cpu_prepare(struct evlist *evlist, struct target *target)
>  {
> -       int err;
> +       int err, fd, i;
> +       int ncpus = 1, ntasks = 1;
>
>         if (off_cpu_config(evlist) < 0) {
>                 pr_err("Failed to config off-cpu BPF event\n");
>                 return -1;
>         }
>
> -       set_max_rlimit();
> -
> -       skel = off_cpu_bpf__open_and_load();
> +       skel = off_cpu_bpf__open();
>         if (!skel) {
>                 pr_err("Failed to open off-cpu BPF skeleton\n");
>                 return -1;
>         }
>
> +       /* don't need to set cpu filter for system-wide mode */
> +       if (target->cpu_list) {
> +               ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
> +               bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
> +       }
> +
> +       if (target__has_task(target)) {
> +               ntasks = perf_thread_map__nr(evlist->core.threads);
> +               bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
> +       }
> +
> +       set_max_rlimit();
> +
> +       err = off_cpu_bpf__load(skel);
> +       if (err) {
> +               pr_err("Failed to load off-cpu skeleton\n");
> +               goto out;
> +       }
> +
> +       if (target->cpu_list) {
> +               u32 cpu;
> +               u8 val = 1;
> +
> +               skel->bss->has_cpu = 1;
> +               fd = bpf_map__fd(skel->maps.cpu_filter);
> +
> +               for (i = 0; i < ncpus; i++) {
> +                       cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
> +                       bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);

Perhaps more concise with a for_each:

perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.user_requested_cpus)
  bpf_map_update_elem(fd, &cpu.cpu, &val, BPF_ANY);

> +               }
> +       }
> +
> +       if (target__has_task(target)) {
> +               u32 pid;
> +               u8 val = 1;
> +
> +               skel->bss->has_task = 1;
> +               fd = bpf_map__fd(skel->maps.task_filter);
> +
> +               for (i = 0; i < ntasks; i++) {
> +                       pid = perf_thread_map__pid(evlist->core.threads, i);
> +                       bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
> +               }
> +       }
> +
>         err = off_cpu_bpf__attach(skel);
>         if (err) {
>                 pr_err("Failed to attach off-cpu BPF skeleton\n");
>                 goto out;
>         }
>
> -       if (perf_hooks__set_hook("record_start", off_cpu_start, NULL) ||
> -           perf_hooks__set_hook("record_end", off_cpu_finish, NULL)) {
> +       if (perf_hooks__set_hook("record_start", off_cpu_start, evlist) ||
> +           perf_hooks__set_hook("record_end", off_cpu_finish, evlist)) {
>                 pr_err("Failed to attach off-cpu skeleton\n");
>                 goto out;
>         }
> diff --git a/tools/perf/util/bpf_skel/off_cpu.bpf.c b/tools/perf/util/bpf_skel/off_cpu.bpf.c
> index 5173ed882fdf..78cdcc8ff863 100644
> --- a/tools/perf/util/bpf_skel/off_cpu.bpf.c
> +++ b/tools/perf/util/bpf_skel/off_cpu.bpf.c
> @@ -49,12 +49,28 @@ struct {
>         __uint(max_entries, MAX_ENTRIES);
>  } off_cpu SEC(".maps");
>
> +struct {
> +       __uint(type, BPF_MAP_TYPE_HASH);
> +       __uint(key_size, sizeof(__u32));
> +       __uint(value_size, sizeof(__u8));
> +       __uint(max_entries, 1);
> +} cpu_filter SEC(".maps");
> +
> +struct {
> +       __uint(type, BPF_MAP_TYPE_HASH);
> +       __uint(key_size, sizeof(__u32));
> +       __uint(value_size, sizeof(__u8));
> +       __uint(max_entries, 1);
> +} task_filter SEC(".maps");
> +
>  /* old kernel task_struct definition */
>  struct task_struct___old {
>         long state;
>  } __attribute__((preserve_access_index));
>
>  int enabled = 0;
> +int has_cpu = 0;
> +int has_task = 0;
>
>  /*
>   * Old kernel used to call it task_struct->state and now it's '__state'.
> @@ -74,6 +90,37 @@ static inline int get_task_state(struct task_struct *t)
>         return BPF_CORE_READ(t_old, state);
>  }
>
> +static inline int can_record(struct task_struct *t, int state)
> +{
> +       /* kernel threads don't have user stack */
> +       if (t->flags & PF_KTHREAD)
> +               return 0;
> +
> +       if (state != TASK_INTERRUPTIBLE &&
> +           state != TASK_UNINTERRUPTIBLE)
> +               return 0;
> +
> +       if (has_cpu) {
> +               __u32 cpu = bpf_get_smp_processor_id();
> +               __u8 *ok;
> +
> +               ok = bpf_map_lookup_elem(&cpu_filter, &cpu);
> +               if (!ok)
> +                       return 0;
> +       }
> +
> +       if (has_task) {
> +               __u8 *ok;
> +               __u32 pid = t->pid;
> +
> +               ok = bpf_map_lookup_elem(&task_filter, &pid);
> +               if (!ok)
> +                       return 0;
> +       }
> +
> +       return 1;
> +}
> +
>  SEC("tp_btf/sched_switch")
>  int on_switch(u64 *ctx)
>  {
> @@ -92,10 +139,7 @@ int on_switch(u64 *ctx)
>
>         ts = bpf_ktime_get_ns();
>
> -       if (prev->flags & PF_KTHREAD)
> -               goto next;
> -       if (state != TASK_INTERRUPTIBLE &&
> -           state != TASK_UNINTERRUPTIBLE)
> +       if (!can_record(prev, state))
>                 goto next;
>
>         stack_id = bpf_get_stackid(ctx, &stacks,
> diff --git a/tools/perf/util/off_cpu.h b/tools/perf/util/off_cpu.h
> index 375d03c424ea..f47af0232e55 100644
> --- a/tools/perf/util/off_cpu.h
> +++ b/tools/perf/util/off_cpu.h
> @@ -2,15 +2,17 @@
>  #define PERF_UTIL_OFF_CPU_H
>
>  struct evlist;
> +struct target;
>  struct perf_session;
>
>  #define OFFCPU_EVENT  "offcpu-time"
>
>  #ifdef HAVE_BPF_SKEL
> -int off_cpu_prepare(struct evlist *evlist);
> +int off_cpu_prepare(struct evlist *evlist, struct target *target);
>  int off_cpu_write(struct perf_session *session);
>  #else
> -static inline int off_cpu_prepare(struct evlist *evlist __maybe_unused)
> +static inline int off_cpu_prepare(struct evlist *evlist __maybe_unused,
> +                                 struct target *target __maybe_unused)
>  {
>         return -1;
>  }
> --
> 2.36.1.124.g0e6072fb45-goog
>
Namhyung Kim May 19, 2022, 9:02 p.m. UTC | #2
On Wed, May 18, 2022 at 9:02 PM Ian Rogers <irogers@google.com> wrote:
>
> On Wed, May 18, 2022 at 3:47 PM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > It should honor cpu and task filtering with -a, -C or -p, -t options.
> >
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > ---
> >  tools/perf/builtin-record.c            |  2 +-
> >  tools/perf/util/bpf_off_cpu.c          | 78 +++++++++++++++++++++++---
> >  tools/perf/util/bpf_skel/off_cpu.bpf.c | 52 +++++++++++++++--
> >  tools/perf/util/off_cpu.h              |  6 +-
> >  4 files changed, 123 insertions(+), 15 deletions(-)
> >
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index 91f88501412e..7f60d2eac0b4 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -907,7 +907,7 @@ static int record__config_text_poke(struct evlist *evlist)
> >
> >  static int record__config_off_cpu(struct record *rec)
> >  {
> > -       return off_cpu_prepare(rec->evlist);
> > +       return off_cpu_prepare(rec->evlist, &rec->opts.target);
> >  }
> >
> >  static bool record__kcore_readable(struct machine *machine)
> > diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
> > index 9ed7aca3f4ac..b5e2d038da50 100644
> > --- a/tools/perf/util/bpf_off_cpu.c
> > +++ b/tools/perf/util/bpf_off_cpu.c
> > @@ -6,6 +6,9 @@
> >  #include "util/off_cpu.h"
> >  #include "util/perf-hooks.h"
> >  #include "util/session.h"
> > +#include "util/target.h"
> > +#include "util/cpumap.h"
> > +#include "util/thread_map.h"
> >  #include <bpf/bpf.h>
> >
> >  #include "bpf_skel/off_cpu.skel.h"
> > @@ -60,8 +63,23 @@ static int off_cpu_config(struct evlist *evlist)
> >         return 0;
> >  }
> >
> > -static void off_cpu_start(void *arg __maybe_unused)
> > +static void off_cpu_start(void *arg)
> >  {
> > +       struct evlist *evlist = arg;
> > +
> > +       /* update task filter for the given workload */
> > +       if (!skel->bss->has_cpu && !skel->bss->has_task &&
> > +           perf_thread_map__pid(evlist->core.threads, 0) != -1) {
> > +               int fd;
> > +               u32 pid;
> > +               u8 val = 1;
> > +
> > +               skel->bss->has_task = 1;
> > +               fd = bpf_map__fd(skel->maps.task_filter);
> > +               pid = perf_thread_map__pid(evlist->core.threads, 0);
> > +               bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
> > +       }
> > +
> >         skel->bss->enabled = 1;
> >  }
> >
> > @@ -71,31 +89,75 @@ static void off_cpu_finish(void *arg __maybe_unused)
> >         off_cpu_bpf__destroy(skel);
> >  }
> >
> > -int off_cpu_prepare(struct evlist *evlist)
> > +int off_cpu_prepare(struct evlist *evlist, struct target *target)
> >  {
> > -       int err;
> > +       int err, fd, i;
> > +       int ncpus = 1, ntasks = 1;
> >
> >         if (off_cpu_config(evlist) < 0) {
> >                 pr_err("Failed to config off-cpu BPF event\n");
> >                 return -1;
> >         }
> >
> > -       set_max_rlimit();
> > -
> > -       skel = off_cpu_bpf__open_and_load();
> > +       skel = off_cpu_bpf__open();
> >         if (!skel) {
> >                 pr_err("Failed to open off-cpu BPF skeleton\n");
> >                 return -1;
> >         }
> >
> > +       /* don't need to set cpu filter for system-wide mode */
> > +       if (target->cpu_list) {
> > +               ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
> > +               bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
> > +       }
> > +
> > +       if (target__has_task(target)) {
> > +               ntasks = perf_thread_map__nr(evlist->core.threads);
> > +               bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
> > +       }
> > +
> > +       set_max_rlimit();
> > +
> > +       err = off_cpu_bpf__load(skel);
> > +       if (err) {
> > +               pr_err("Failed to load off-cpu skeleton\n");
> > +               goto out;
> > +       }
> > +
> > +       if (target->cpu_list) {
> > +               u32 cpu;
> > +               u8 val = 1;
> > +
> > +               skel->bss->has_cpu = 1;
> > +               fd = bpf_map__fd(skel->maps.cpu_filter);
> > +
> > +               for (i = 0; i < ncpus; i++) {
> > +                       cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
> > +                       bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
>
> Perhaps more concise with a for_each:
>
> perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.user_requested_cpus)
>   bpf_map_update_elem(fd, &cpu.cpu, &val, BPF_ANY);

Will change.

Thanks,
Namhyung
Arnaldo Carvalho de Melo May 25, 2022, 11:27 a.m. UTC | #3
Em Thu, May 19, 2022 at 02:02:28PM -0700, Namhyung Kim escreveu:
> On Wed, May 18, 2022 at 9:02 PM Ian Rogers <irogers@google.com> wrote:
> >
> > On Wed, May 18, 2022 at 3:47 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > >
> > > It should honor cpu and task filtering with -a, -C or -p, -t options.
> > >
> > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > > ---
> > >  tools/perf/builtin-record.c            |  2 +-
> > >  tools/perf/util/bpf_off_cpu.c          | 78 +++++++++++++++++++++++---
> > >  tools/perf/util/bpf_skel/off_cpu.bpf.c | 52 +++++++++++++++--
> > >  tools/perf/util/off_cpu.h              |  6 +-
> > >  4 files changed, 123 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > > index 91f88501412e..7f60d2eac0b4 100644
> > > --- a/tools/perf/builtin-record.c
> > > +++ b/tools/perf/builtin-record.c
> > > @@ -907,7 +907,7 @@ static int record__config_text_poke(struct evlist *evlist)
> > >
> > >  static int record__config_off_cpu(struct record *rec)
> > >  {
> > > -       return off_cpu_prepare(rec->evlist);
> > > +       return off_cpu_prepare(rec->evlist, &rec->opts.target);
> > >  }
> > >
> > >  static bool record__kcore_readable(struct machine *machine)
> > > diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
> > > index 9ed7aca3f4ac..b5e2d038da50 100644
> > > --- a/tools/perf/util/bpf_off_cpu.c
> > > +++ b/tools/perf/util/bpf_off_cpu.c
> > > @@ -6,6 +6,9 @@
> > >  #include "util/off_cpu.h"
> > >  #include "util/perf-hooks.h"
> > >  #include "util/session.h"
> > > +#include "util/target.h"
> > > +#include "util/cpumap.h"
> > > +#include "util/thread_map.h"
> > >  #include <bpf/bpf.h>
> > >
> > >  #include "bpf_skel/off_cpu.skel.h"
> > > @@ -60,8 +63,23 @@ static int off_cpu_config(struct evlist *evlist)
> > >         return 0;
> > >  }
> > >
> > > -static void off_cpu_start(void *arg __maybe_unused)
> > > +static void off_cpu_start(void *arg)
> > >  {
> > > +       struct evlist *evlist = arg;
> > > +
> > > +       /* update task filter for the given workload */
> > > +       if (!skel->bss->has_cpu && !skel->bss->has_task &&
> > > +           perf_thread_map__pid(evlist->core.threads, 0) != -1) {
> > > +               int fd;
> > > +               u32 pid;
> > > +               u8 val = 1;
> > > +
> > > +               skel->bss->has_task = 1;
> > > +               fd = bpf_map__fd(skel->maps.task_filter);
> > > +               pid = perf_thread_map__pid(evlist->core.threads, 0);
> > > +               bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
> > > +       }
> > > +
> > >         skel->bss->enabled = 1;
> > >  }
> > >
> > > @@ -71,31 +89,75 @@ static void off_cpu_finish(void *arg __maybe_unused)
> > >         off_cpu_bpf__destroy(skel);
> > >  }
> > >
> > > -int off_cpu_prepare(struct evlist *evlist)
> > > +int off_cpu_prepare(struct evlist *evlist, struct target *target)
> > >  {
> > > -       int err;
> > > +       int err, fd, i;
> > > +       int ncpus = 1, ntasks = 1;
> > >
> > >         if (off_cpu_config(evlist) < 0) {
> > >                 pr_err("Failed to config off-cpu BPF event\n");
> > >                 return -1;
> > >         }
> > >
> > > -       set_max_rlimit();
> > > -
> > > -       skel = off_cpu_bpf__open_and_load();
> > > +       skel = off_cpu_bpf__open();
> > >         if (!skel) {
> > >                 pr_err("Failed to open off-cpu BPF skeleton\n");
> > >                 return -1;
> > >         }
> > >
> > > +       /* don't need to set cpu filter for system-wide mode */
> > > +       if (target->cpu_list) {
> > > +               ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
> > > +               bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
> > > +       }
> > > +
> > > +       if (target__has_task(target)) {
> > > +               ntasks = perf_thread_map__nr(evlist->core.threads);
> > > +               bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
> > > +       }
> > > +
> > > +       set_max_rlimit();
> > > +
> > > +       err = off_cpu_bpf__load(skel);
> > > +       if (err) {
> > > +               pr_err("Failed to load off-cpu skeleton\n");
> > > +               goto out;
> > > +       }
> > > +
> > > +       if (target->cpu_list) {
> > > +               u32 cpu;
> > > +               u8 val = 1;
> > > +
> > > +               skel->bss->has_cpu = 1;
> > > +               fd = bpf_map__fd(skel->maps.cpu_filter);
> > > +
> > > +               for (i = 0; i < ncpus; i++) {
> > > +                       cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
> > > +                       bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
> >
> > Perhaps more concise with a for_each:
> >
> > perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.user_requested_cpus)
> >   bpf_map_update_elem(fd, &cpu.cpu, &val, BPF_ANY);

So I'll wait for a new version of this patchset.

- Arnaldo
Arnaldo Carvalho de Melo May 25, 2022, 11:44 a.m. UTC | #4
Em Wed, May 25, 2022 at 08:27:38AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, May 19, 2022 at 02:02:28PM -0700, Namhyung Kim escreveu:
> > On Wed, May 18, 2022 at 9:02 PM Ian Rogers <irogers@google.com> wrote:
> > >
> > > On Wed, May 18, 2022 at 3:47 PM Namhyung Kim <namhyung@kernel.org> wrote:
> > > >
> > > > It should honor cpu and task filtering with -a, -C or -p, -t options.
> > > >
> > > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > > > ---
> > > >  tools/perf/builtin-record.c            |  2 +-
> > > >  tools/perf/util/bpf_off_cpu.c          | 78 +++++++++++++++++++++++---
> > > >  tools/perf/util/bpf_skel/off_cpu.bpf.c | 52 +++++++++++++++--
> > > >  tools/perf/util/off_cpu.h              |  6 +-
> > > >  4 files changed, 123 insertions(+), 15 deletions(-)
> > > >
> > > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > > > index 91f88501412e..7f60d2eac0b4 100644
> > > > --- a/tools/perf/builtin-record.c
> > > > +++ b/tools/perf/builtin-record.c
> > > > @@ -907,7 +907,7 @@ static int record__config_text_poke(struct evlist *evlist)
> > > >
> > > >  static int record__config_off_cpu(struct record *rec)
> > > >  {
> > > > -       return off_cpu_prepare(rec->evlist);
> > > > +       return off_cpu_prepare(rec->evlist, &rec->opts.target);
> > > >  }
> > > >
> > > >  static bool record__kcore_readable(struct machine *machine)
> > > > diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
> > > > index 9ed7aca3f4ac..b5e2d038da50 100644
> > > > --- a/tools/perf/util/bpf_off_cpu.c
> > > > +++ b/tools/perf/util/bpf_off_cpu.c
> > > > @@ -6,6 +6,9 @@
> > > >  #include "util/off_cpu.h"
> > > >  #include "util/perf-hooks.h"
> > > >  #include "util/session.h"
> > > > +#include "util/target.h"
> > > > +#include "util/cpumap.h"
> > > > +#include "util/thread_map.h"
> > > >  #include <bpf/bpf.h>
> > > >
> > > >  #include "bpf_skel/off_cpu.skel.h"
> > > > @@ -60,8 +63,23 @@ static int off_cpu_config(struct evlist *evlist)
> > > >         return 0;
> > > >  }
> > > >
> > > > -static void off_cpu_start(void *arg __maybe_unused)
> > > > +static void off_cpu_start(void *arg)
> > > >  {
> > > > +       struct evlist *evlist = arg;
> > > > +
> > > > +       /* update task filter for the given workload */
> > > > +       if (!skel->bss->has_cpu && !skel->bss->has_task &&
> > > > +           perf_thread_map__pid(evlist->core.threads, 0) != -1) {
> > > > +               int fd;
> > > > +               u32 pid;
> > > > +               u8 val = 1;
> > > > +
> > > > +               skel->bss->has_task = 1;
> > > > +               fd = bpf_map__fd(skel->maps.task_filter);
> > > > +               pid = perf_thread_map__pid(evlist->core.threads, 0);
> > > > +               bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
> > > > +       }
> > > > +
> > > >         skel->bss->enabled = 1;
> > > >  }
> > > >
> > > > @@ -71,31 +89,75 @@ static void off_cpu_finish(void *arg __maybe_unused)
> > > >         off_cpu_bpf__destroy(skel);
> > > >  }
> > > >
> > > > -int off_cpu_prepare(struct evlist *evlist)
> > > > +int off_cpu_prepare(struct evlist *evlist, struct target *target)
> > > >  {
> > > > -       int err;
> > > > +       int err, fd, i;
> > > > +       int ncpus = 1, ntasks = 1;
> > > >
> > > >         if (off_cpu_config(evlist) < 0) {
> > > >                 pr_err("Failed to config off-cpu BPF event\n");
> > > >                 return -1;
> > > >         }
> > > >
> > > > -       set_max_rlimit();
> > > > -
> > > > -       skel = off_cpu_bpf__open_and_load();
> > > > +       skel = off_cpu_bpf__open();
> > > >         if (!skel) {
> > > >                 pr_err("Failed to open off-cpu BPF skeleton\n");
> > > >                 return -1;
> > > >         }
> > > >
> > > > +       /* don't need to set cpu filter for system-wide mode */
> > > > +       if (target->cpu_list) {
> > > > +               ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
> > > > +               bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
> > > > +       }
> > > > +
> > > > +       if (target__has_task(target)) {
> > > > +               ntasks = perf_thread_map__nr(evlist->core.threads);
> > > > +               bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
> > > > +       }
> > > > +
> > > > +       set_max_rlimit();
> > > > +
> > > > +       err = off_cpu_bpf__load(skel);
> > > > +       if (err) {
> > > > +               pr_err("Failed to load off-cpu skeleton\n");
> > > > +               goto out;
> > > > +       }
> > > > +
> > > > +       if (target->cpu_list) {
> > > > +               u32 cpu;
> > > > +               u8 val = 1;
> > > > +
> > > > +               skel->bss->has_cpu = 1;
> > > > +               fd = bpf_map__fd(skel->maps.cpu_filter);
> > > > +
> > > > +               for (i = 0; i < ncpus; i++) {
> > > > +                       cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
> > > > +                       bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
> > >
> > > Perhaps more concise with a for_each:
> > >
> > > perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.user_requested_cpus)
> > >   bpf_map_update_elem(fd, &cpu.cpu, &val, BPF_ANY);
> 
> So I'll wait for a new version of this patchset.

I take that back, will apply and this can be a follow up patch, right?

- Arnaldo
Arnaldo Carvalho de Melo May 25, 2022, 2:06 p.m. UTC | #5
Em Wed, May 25, 2022 at 08:44:38AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Wed, May 25, 2022 at 08:27:38AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Thu, May 19, 2022 at 02:02:28PM -0700, Namhyung Kim escreveu:
> > > On Wed, May 18, 2022 at 9:02 PM Ian Rogers <irogers@google.com> wrote:
> > > > Perhaps more concise with a for_each:

> > > > perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.user_requested_cpus)
> > > >   bpf_map_update_elem(fd, &cpu.cpu, &val, BPF_ANY);

> > So I'll wait for a new version of this patchset.

> I take that back, will apply and this can be a follow up patch, right?

I tested it and added some committer notes, everything is now at my
tmp.perf/core branch and will transition to perf/core on its way to 5.19
later today, after tests finish.

- Arnaldo
diff mbox series

Patch

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 91f88501412e..7f60d2eac0b4 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -907,7 +907,7 @@  static int record__config_text_poke(struct evlist *evlist)
 
 static int record__config_off_cpu(struct record *rec)
 {
-	return off_cpu_prepare(rec->evlist);
+	return off_cpu_prepare(rec->evlist, &rec->opts.target);
 }
 
 static bool record__kcore_readable(struct machine *machine)
diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
index 9ed7aca3f4ac..b5e2d038da50 100644
--- a/tools/perf/util/bpf_off_cpu.c
+++ b/tools/perf/util/bpf_off_cpu.c
@@ -6,6 +6,9 @@ 
 #include "util/off_cpu.h"
 #include "util/perf-hooks.h"
 #include "util/session.h"
+#include "util/target.h"
+#include "util/cpumap.h"
+#include "util/thread_map.h"
 #include <bpf/bpf.h>
 
 #include "bpf_skel/off_cpu.skel.h"
@@ -60,8 +63,23 @@  static int off_cpu_config(struct evlist *evlist)
 	return 0;
 }
 
-static void off_cpu_start(void *arg __maybe_unused)
+static void off_cpu_start(void *arg)
 {
+	struct evlist *evlist = arg;
+
+	/* update task filter for the given workload */
+	if (!skel->bss->has_cpu && !skel->bss->has_task &&
+	    perf_thread_map__pid(evlist->core.threads, 0) != -1) {
+		int fd;
+		u32 pid;
+		u8 val = 1;
+
+		skel->bss->has_task = 1;
+		fd = bpf_map__fd(skel->maps.task_filter);
+		pid = perf_thread_map__pid(evlist->core.threads, 0);
+		bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
+	}
+
 	skel->bss->enabled = 1;
 }
 
@@ -71,31 +89,75 @@  static void off_cpu_finish(void *arg __maybe_unused)
 	off_cpu_bpf__destroy(skel);
 }
 
-int off_cpu_prepare(struct evlist *evlist)
+int off_cpu_prepare(struct evlist *evlist, struct target *target)
 {
-	int err;
+	int err, fd, i;
+	int ncpus = 1, ntasks = 1;
 
 	if (off_cpu_config(evlist) < 0) {
 		pr_err("Failed to config off-cpu BPF event\n");
 		return -1;
 	}
 
-	set_max_rlimit();
-
-	skel = off_cpu_bpf__open_and_load();
+	skel = off_cpu_bpf__open();
 	if (!skel) {
 		pr_err("Failed to open off-cpu BPF skeleton\n");
 		return -1;
 	}
 
+	/* don't need to set cpu filter for system-wide mode */
+	if (target->cpu_list) {
+		ncpus = perf_cpu_map__nr(evlist->core.user_requested_cpus);
+		bpf_map__set_max_entries(skel->maps.cpu_filter, ncpus);
+	}
+
+	if (target__has_task(target)) {
+		ntasks = perf_thread_map__nr(evlist->core.threads);
+		bpf_map__set_max_entries(skel->maps.task_filter, ntasks);
+	}
+
+	set_max_rlimit();
+
+	err = off_cpu_bpf__load(skel);
+	if (err) {
+		pr_err("Failed to load off-cpu skeleton\n");
+		goto out;
+	}
+
+	if (target->cpu_list) {
+		u32 cpu;
+		u8 val = 1;
+
+		skel->bss->has_cpu = 1;
+		fd = bpf_map__fd(skel->maps.cpu_filter);
+
+		for (i = 0; i < ncpus; i++) {
+			cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, i).cpu;
+			bpf_map_update_elem(fd, &cpu, &val, BPF_ANY);
+		}
+	}
+
+	if (target__has_task(target)) {
+		u32 pid;
+		u8 val = 1;
+
+		skel->bss->has_task = 1;
+		fd = bpf_map__fd(skel->maps.task_filter);
+
+		for (i = 0; i < ntasks; i++) {
+			pid = perf_thread_map__pid(evlist->core.threads, i);
+			bpf_map_update_elem(fd, &pid, &val, BPF_ANY);
+		}
+	}
+
 	err = off_cpu_bpf__attach(skel);
 	if (err) {
 		pr_err("Failed to attach off-cpu BPF skeleton\n");
 		goto out;
 	}
 
-	if (perf_hooks__set_hook("record_start", off_cpu_start, NULL) ||
-	    perf_hooks__set_hook("record_end", off_cpu_finish, NULL)) {
+	if (perf_hooks__set_hook("record_start", off_cpu_start, evlist) ||
+	    perf_hooks__set_hook("record_end", off_cpu_finish, evlist)) {
 		pr_err("Failed to attach off-cpu skeleton\n");
 		goto out;
 	}
diff --git a/tools/perf/util/bpf_skel/off_cpu.bpf.c b/tools/perf/util/bpf_skel/off_cpu.bpf.c
index 5173ed882fdf..78cdcc8ff863 100644
--- a/tools/perf/util/bpf_skel/off_cpu.bpf.c
+++ b/tools/perf/util/bpf_skel/off_cpu.bpf.c
@@ -49,12 +49,28 @@  struct {
 	__uint(max_entries, MAX_ENTRIES);
 } off_cpu SEC(".maps");
 
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u8));
+	__uint(max_entries, 1);
+} cpu_filter SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u8));
+	__uint(max_entries, 1);
+} task_filter SEC(".maps");
+
 /* old kernel task_struct definition */
 struct task_struct___old {
 	long state;
 } __attribute__((preserve_access_index));
 
 int enabled = 0;
+int has_cpu = 0;
+int has_task = 0;
 
 /*
  * Old kernel used to call it task_struct->state and now it's '__state'.
@@ -74,6 +90,37 @@  static inline int get_task_state(struct task_struct *t)
 	return BPF_CORE_READ(t_old, state);
 }
 
+static inline int can_record(struct task_struct *t, int state)
+{
+	/* kernel threads don't have user stack */
+	if (t->flags & PF_KTHREAD)
+		return 0;
+
+	if (state != TASK_INTERRUPTIBLE &&
+	    state != TASK_UNINTERRUPTIBLE)
+		return 0;
+
+	if (has_cpu) {
+		__u32 cpu = bpf_get_smp_processor_id();
+		__u8 *ok;
+
+		ok = bpf_map_lookup_elem(&cpu_filter, &cpu);
+		if (!ok)
+			return 0;
+	}
+
+	if (has_task) {
+		__u8 *ok;
+		__u32 pid = t->pid;
+
+		ok = bpf_map_lookup_elem(&task_filter, &pid);
+		if (!ok)
+			return 0;
+	}
+
+	return 1;
+}
+
 SEC("tp_btf/sched_switch")
 int on_switch(u64 *ctx)
 {
@@ -92,10 +139,7 @@  int on_switch(u64 *ctx)
 
 	ts = bpf_ktime_get_ns();
 
-	if (prev->flags & PF_KTHREAD)
-		goto next;
-	if (state != TASK_INTERRUPTIBLE &&
-	    state != TASK_UNINTERRUPTIBLE)
+	if (!can_record(prev, state))
 		goto next;
 
 	stack_id = bpf_get_stackid(ctx, &stacks,
diff --git a/tools/perf/util/off_cpu.h b/tools/perf/util/off_cpu.h
index 375d03c424ea..f47af0232e55 100644
--- a/tools/perf/util/off_cpu.h
+++ b/tools/perf/util/off_cpu.h
@@ -2,15 +2,17 @@ 
 #define PERF_UTIL_OFF_CPU_H
 
 struct evlist;
+struct target;
 struct perf_session;
 
 #define OFFCPU_EVENT  "offcpu-time"
 
 #ifdef HAVE_BPF_SKEL
-int off_cpu_prepare(struct evlist *evlist);
+int off_cpu_prepare(struct evlist *evlist, struct target *target);
 int off_cpu_write(struct perf_session *session);
 #else
-static inline int off_cpu_prepare(struct evlist *evlist __maybe_unused)
+static inline int off_cpu_prepare(struct evlist *evlist __maybe_unused,
+				  struct target *target __maybe_unused)
 {
 	return -1;
 }