Merge pull request #1496 from palmtenor/fix_lost

Fix and improvement for perf_reader's lost_cb

src/cc/libbpf.h

@@ -68,7 +68,7 @@ int bpf_open_raw_sock(const char *name);
 typedef void (*perf_reader_cb)(void *cb_cookie, int pid, uint64_t callchain_num,
                                void *callchain);
 typedef void (*perf_reader_raw_cb)(void *cb_cookie, void *raw, int raw_size);
-typedef void (*perf_reader_lost_cb)(uint64_t lost);
+typedef void (*perf_reader_lost_cb)(void *cb_cookie, uint64_t lost);
 
 void *bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type,
                         const char *ev_name, const char *fn_name,

src/cc/perf_reader.c

@@ -243,9 +243,17 @@ void perf_reader_event_read(struct perf_reader *reader) {
     }
 
     if (e->type == PERF_RECORD_LOST) {
-      uint64_t lost = *(uint64_t *)(ptr + sizeof(*e));
+      /*
+       * struct {
+       *    struct perf_event_header    header;
+       *    u64                id;
+       *    u64                lost;
+       *    struct sample_id        sample_id;
+       * };
+       */
+      uint64_t lost = *(uint64_t *)(ptr + sizeof(*e) + sizeof(uint64_t));
       if (reader->lost_cb) {
-        reader->lost_cb(lost);
+        reader->lost_cb(reader->cb_cookie, lost);
       } else {
         fprintf(stderr, "Possibly lost %" PRIu64 " samples\n", lost);
       }

src/lua/bcc/libbcc.lua

@@ -41,7 +41,7 @@ int bpf_open_raw_sock(const char *name);
 
 typedef void (*perf_reader_cb)(void *cb_cookie, int pid, uint64_t callchain_num, void *callchain);
 typedef void (*perf_reader_raw_cb)(void *cb_cookie, void *raw, int raw_size);
-typedef void (*perf_reader_lost_cb)(uint64_t lost);
+typedef void (*perf_reader_lost_cb)(void *cb_cookie, uint64_t lost);
 
 void *bpf_attach_kprobe(int progfd, int attach_type, const char *ev_name,
                         const char *fn_name, perf_reader_cb cb,

src/lua/bcc/table.lua

@@ -252,8 +252,8 @@ function PerfEventArray:_open_perf_buffer(cpu, callback, ctype, page_cnt, lost_c
   local _lost_cb = nil
   if lost_cb then
     _lost_cb = ffi.cast("perf_reader_lost_cb",
-      function (lost)
-        lost_cb(lost)
+      function (cookie, lost)
+        lost_cb(cookie, lost)
       end)
   end
 

src/python/bcc/libbcc.py

@@ -89,7 +89,7 @@ lib.bpf_attach_kprobe.restype = ct.c_void_p
 _CB_TYPE = ct.CFUNCTYPE(None, ct.py_object, ct.c_int,
         ct.c_ulonglong, ct.POINTER(ct.c_ulonglong))
 _RAW_CB_TYPE = ct.CFUNCTYPE(None, ct.py_object, ct.c_void_p, ct.c_int)
-_LOST_CB_TYPE = ct.CFUNCTYPE(None, ct.c_ulonglong)
+_LOST_CB_TYPE = ct.CFUNCTYPE(None, ct.py_object, ct.c_ulonglong)
 lib.bpf_attach_kprobe.argtypes = [ct.c_int, ct.c_int, ct.c_char_p, ct.c_char_p,
         _CB_TYPE, ct.py_object]
 lib.bpf_detach_kprobe.restype = ct.c_int