lkml.org 
[lkml]   [2019]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH v5 perf,bpf 07/15] perf, bpf: save bpf_prog_info information as headers to perf.data
    On Mon, Mar 04, 2019 at 07:41:10PM +0000, Song Liu wrote:
    >
    >
    > > On Mar 4, 2019, at 5:52 AM, Jiri Olsa <jolsa@redhat.com> wrote:
    > >
    > > On Wed, Feb 27, 2019 at 09:06:35PM -0800, Song Liu wrote:
    > >> This patch enables perf-record to save bpf_prog_info information as
    > >> headers to perf.data. A new header type HEADER_BPF_PROG_INFO is
    > >> introduced for this data.
    > >>
    > >> Signed-off-by: Song Liu <songliubraving@fb.com>
    > >> ---
    > >> tools/perf/util/header.c | 143 ++++++++++++++++++++++++++++++++++++++-
    > >> tools/perf/util/header.h | 1 +
    > >> 2 files changed, 143 insertions(+), 1 deletion(-)
    > >>
    > >> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
    > >> index 4b88de5e9192..16f5bedb0b7d 100644
    > >> --- a/tools/perf/util/header.c
    > >> +++ b/tools/perf/util/header.c
    > >> @@ -18,6 +18,7 @@
    > >> #include <sys/utsname.h>
    > >> #include <linux/time64.h>
    > >> #include <dirent.h>
    > >> +#include <bpf/libbpf.h>
    > >>
    > >> #include "evlist.h"
    > >> #include "evsel.h"
    > >> @@ -39,6 +40,7 @@
    > >> #include "tool.h"
    > >> #include "time-utils.h"
    > >> #include "units.h"
    > >> +#include "bpf-event.h"
    > >>
    > >> #include "sane_ctype.h"
    > >>
    > >> @@ -1074,6 +1076,51 @@ static int write_clockid(struct feat_fd *ff,
    > >> sizeof(ff->ph->env.clockid_res_ns));
    > >> }
    > >>
    > >> +static int write_bpf_prog_info(struct feat_fd *ff,
    > >> + struct perf_evlist *evlist __maybe_unused)
    > >> +{
    > >> + struct perf_env *env = &ff->ph->env;
    > >> + struct rb_root *root;
    > >> + struct rb_node *next;
    > >> + u32 count = 0;
    > >> + int ret;
    > >> +
    > >> + down_read(&env->bpf_progs.lock);
    > >> +
    > >> + root = &env->bpf_progs.infos;
    > >> + next = rb_first(root);
    > >> + while (next) {
    > >> + ++count;
    > >> + next = rb_next(next);
    > >> + }
    > >> +
    > >> + ret = do_write(ff, &count, sizeof(count));
    > >> +
    > >> + if (ret < 0)
    > >> + goto out;
    > >> +
    > >> + next = rb_first(root);
    > >> + while (next) {
    > >> + struct bpf_prog_info_node *node;
    > >> + size_t len;
    > >> +
    > >> + node = rb_entry(next, struct bpf_prog_info_node, rb_node);
    > >> + next = rb_next(&node->rb_node);
    > >> + len = sizeof(struct bpf_prog_info_linear) +
    > >> + node->info_linear->data_len;
    > >> +
    > >> + /* before writing to file, translate address to offset */
    > >> + bpf_program__bpil_addr_to_offs(node->info_linear);
    > >> + ret = do_write(ff, node->info_linear, len);
    > >> + bpf_program__bpil_offs_to_addr(node->info_linear);
    > >
    > > what's the reason to call this before the error check?
    >
    > This will translate the all the pointers to the right address
    > (instead of offsets). We only need the offsets when writing to
    > files. With this approach, the data is not changed whether the
    > function succeeds or not. It is probably not necessary right
    > now. But I think this may save us some debugging efforts in
    > the future.

    ok, please make comment with this

    jirka

    \
     
     \ /
      Last update: 2019-03-04 21:38    [W:2.236 / U:0.356 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site