From 8cd7aa29ef3c79e6c7138e35d8f25f2c36879cb7 Mon Sep 17 00:00:00 2001
From: ezra buchla <emb@catfact.net>
Date: Sat, 21 Oct 2023 07:26:27 -0700
Subject: [PATCH] add cpu_time (#1718)

---
 matron/src/hardware/cpu_time.c | 29 +++++++++++++++++++++++++++++
 matron/src/hardware/cpu_time.h |  8 ++++++++
 matron/src/system_cmd.c        | 11 -----------
 matron/src/weaver.c            | 18 ++++++++++++++++++
 matron/wscript                 |  1 +
 5 files changed, 56 insertions(+), 11 deletions(-)
 create mode 100644 matron/src/hardware/cpu_time.c
 create mode 100644 matron/src/hardware/cpu_time.h

diff --git a/matron/src/hardware/cpu_time.c b/matron/src/hardware/cpu_time.c
new file mode 100644
index 000000000..4d13c19f0
--- /dev/null
+++ b/matron/src/hardware/cpu_time.c
@@ -0,0 +1,29 @@
+#include "cpu_time.h"
+
+#include <time.h>
+
+struct timespec t0;
+
+static struct timespec diff(const struct timespec *start, const struct timespec *end)
+{
+    struct timespec temp;
+    if ((end->tv_nsec - start->tv_nsec)<0) {
+        temp.tv_sec = end->tv_sec - start->tv_sec - 1;
+        temp.tv_nsec = 1000000000 + end->tv_nsec - start->tv_nsec;
+    } else {
+        temp.tv_sec = end->tv_sec - start->tv_sec;
+        temp.tv_nsec = end->tv_nsec - start->tv_nsec;
+    }
+    return temp;
+}
+
+void cpu_time_start() {
+    clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &t0);
+ }
+
+unsigned long int cpu_time_get_delta_ns() {
+    struct timespec t1;
+    clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &t1);
+    struct timespec delta = diff(&t0, &t1);
+    return (delta.tv_sec * 1000000000) + delta.tv_nsec;
+ }
\ No newline at end of file
diff --git a/matron/src/hardware/cpu_time.h b/matron/src/hardware/cpu_time.h
new file mode 100644
index 000000000..bb7198c08
--- /dev/null
+++ b/matron/src/hardware/cpu_time.h
@@ -0,0 +1,8 @@
+// extremely simple CPU time measurement module, for benchmarking
+// sets a single reference point, and computes time deltas since that point
+
+#pragma once
+
+extern void cpu_time_start();
+
+extern unsigned long int cpu_time_get_delta_ns();
\ No newline at end of file
diff --git a/matron/src/system_cmd.c b/matron/src/system_cmd.c
index b3fcf199f..936e1a618 100644
--- a/matron/src/system_cmd.c
+++ b/matron/src/system_cmd.c
@@ -73,19 +73,8 @@ void *run_cmd(void *cmd) {
             strncat(capture, line, capacity);
         }
         capacity -= len;
-
-#if 1 // test..
-	fprintf(stderr, "last line: \n\t%s\n", line);
-	// fprintf(stderr, "current buffer: \n\t %s\n", line);
-	fprintf(stderr, "remaining capacity: %d bytes\n", capacity);
-#endif
-
     } while (capacity > 0); // ... or, stop if buffer is full
 
-#if 0 // test...
-    fprintf(stderr, "finished line loop; full buffer: \n");    
-    fprintf(stderr, "%s\n", capture);
-#endif
 
     // just use memcpy and include the null terminator
     size_t len = strlen(capture) + 1;
diff --git a/matron/src/weaver.c b/matron/src/weaver.c
index 170ce2f25..c65b779ca 100644
--- a/matron/src/weaver.c
+++ b/matron/src/weaver.c
@@ -28,6 +28,7 @@
 #include "clocks/clock_internal.h"
 #include "clocks/clock_link.h"
 #include "clocks/clock_scheduler.h"
+#include "cpu_time.h"
 #include "device_crow.h"
 #include "device_hid.h"
 #include "device_midi.h"
@@ -288,6 +289,10 @@ static int _clock_get_tempo(lua_State *l);
 static int _audio_get_cpu_load(lua_State *l);
 static int _audio_get_xrun_count(lua_State *l);
 
+// CPU time
+static int _cpu_time_start_timer(lua_State *l);
+static int _cpu_time_get_delta(lua_State *l);
+
 // platform detection (CM3 vs PI3 vs OTHER)
 static int _platform(lua_State *l);
 
@@ -548,6 +553,9 @@ void w_init(void) {
     lua_register_norns("audio_get_cpu_load", &_audio_get_cpu_load);
     lua_register_norns("audio_get_xrun_count", &_audio_get_xrun_count);
 
+    lua_register_norns("cpu_time_start_timer", &_cpu_time_start_timer);
+    lua_register_norns("cpu_time_get_delta", &_cpu_time_get_delta);
+
     // platform
     lua_register_norns("platform", &_platform);
 
@@ -1973,6 +1981,16 @@ int _audio_get_xrun_count(lua_State *l) {
     return 1;
 }
 
+int _cpu_time_start_timer(lua_State *l) {
+    cpu_time_start();
+    return 0;
+}
+
+int _cpu_time_get_delta(lua_State *l) {
+    lua_pushnumber(l, cpu_time_get_delta_ns());
+    return 1;
+}
+
 //--------------------------------------------------
 //--- define lua handlers for system callbacks
 
diff --git a/matron/wscript b/matron/wscript
index b98e9fca8..55765bf22 100644
--- a/matron/wscript
+++ b/matron/wscript
@@ -12,6 +12,7 @@ def build(bld):
         'src/device/device_crow.c',
         'src/osc.c',
         'src/hardware/battery.c',
+        'src/hardware/cpu_time.c',
         'src/hardware/i2c.c',
         'src/hardware/input.c',
         'src/hardware/io.c',