ebpf: increase number of stack delta buckets

With #230 an issue is reported, where the number of stack delta buckets is not sufficient. Increase stack delta bucket to be able to unwind also such executables. Signed-off-by: Florian Lehner <[email protected]>
open-telemetry · Nov 8, 2024 · d823d2f · d823d2f
1 parent 8ea42ea
commit d823d2f
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Showing 7 changed files with 11 additions and 3 deletions.
diff --git a/processmanager/ebpf/ebpf.go b/processmanager/ebpf/ebpf.go
@@ -135,6 +135,8 @@ var outerMapsName = [...]string{
 	"exe_id_to_19_stack_deltas",
 	"exe_id_to_20_stack_deltas",
 	"exe_id_to_21_stack_deltas",
+	"exe_id_to_22_stack_deltas",
+	"exe_id_to_23_stack_deltas",
 }
 
 // Compile time check to make sure ebpfMapsImpl satisfies the interface .

diff --git a/processmanager/ebpf/ebpf_test.go b/processmanager/ebpf/ebpf_test.go
@@ -38,6 +38,6 @@ func TestMapID(t *testing.T) {
 		})
 	}
 
-	_, err := getMapID(1 << 22)
+	_, err := getMapID(1 << 24)
 	require.Error(t, err)
 }
diff --git a/support/ebpf/extmaps.h b/support/ebpf/extmaps.h
@@ -38,6 +38,8 @@ extern bpf_map_def exe_id_to_18_stack_deltas;
 extern bpf_map_def exe_id_to_19_stack_deltas;
 extern bpf_map_def exe_id_to_20_stack_deltas;
 extern bpf_map_def exe_id_to_21_stack_deltas;
+extern bpf_map_def exe_id_to_22_stack_deltas;
+extern bpf_map_def exe_id_to_23_stack_deltas;
 extern bpf_map_def hotspot_procs;
 extern bpf_map_def kernel_stackmap;
 extern bpf_map_def dotnet_procs;

diff --git a/support/ebpf/native_stack_trace.ebpf.c b/support/ebpf/native_stack_trace.ebpf.c
@@ -37,6 +37,8 @@ STACK_DELTA_BUCKET(18);
 STACK_DELTA_BUCKET(19);
 STACK_DELTA_BUCKET(20);
 STACK_DELTA_BUCKET(21);
+STACK_DELTA_BUCKET(22);
+STACK_DELTA_BUCKET(23);
 
 // Unwind info value for invalid stack delta
 #define STACK_DELTA_INVALID (STACK_DELTA_COMMAND_FLAG | UNWIND_COMMAND_INVALID)
@@ -154,6 +156,8 @@ void *get_stack_delta_map(int mapID) {
   case 19: return &exe_id_to_19_stack_deltas;
   case 20: return &exe_id_to_20_stack_deltas;
   case 21: return &exe_id_to_21_stack_deltas;
+  case 22: return &exe_id_to_22_stack_deltas;
+  case 23: return &exe_id_to_23_stack_deltas;
   default: return NULL;
   }
 }

diff --git a/support/ebpf/tracer.ebpf.release.amd64 b/support/ebpf/tracer.ebpf.release.amd64
diff --git a/support/ebpf/tracer.ebpf.release.arm64 b/support/ebpf/tracer.ebpf.release.arm64
diff --git a/support/ebpf/types.h b/support/ebpf/types.h
@@ -831,8 +831,8 @@ void decode_bias_and_unwind_program(u64 bias_and_unwind_program, u64* bias, int*
 
 // Smallest stack delta bucket that holds up to 2^8 entries
 #define STACK_DELTA_BUCKET_SMALLEST 8
-// Largest stack delta bucket that holds up to 2^21 entries
-#define STACK_DELTA_BUCKET_LARGEST 21
+// Largest stack delta bucket that holds up to 2^23 entries
+#define STACK_DELTA_BUCKET_LARGEST 23
 
 // Struct of the `system_config` map. Contains various configuration variables
 // determined and set by the host agent.