From 29031174ae315844f5847fda0df35b2807c3034c Mon Sep 17 00:00:00 2001
From: "Rafael G. Martins" <rafael@rafaelmartins.eng.br>
Date: Sat, 2 Feb 2019 16:14:26 +0100
Subject: blogc: optimized getrusage calls

---
 src/blogc/funcvars.c | 11 ++++-------
 src/blogc/funcvars.h |  2 +-
 src/blogc/rusage.c   | 54 ++++++++++++++++++++++------------------------------
 src/blogc/rusage.h   |  7 +++----
 4 files changed, 31 insertions(+), 43 deletions(-)

diff --git a/src/blogc/funcvars.c b/src/blogc/funcvars.c
index 8524568..4fc12cf 100644
--- a/src/blogc/funcvars.c
+++ b/src/blogc/funcvars.c
@@ -21,8 +21,8 @@ static const struct func_map {
 } funcs[] = {
 
 #ifdef HAVE_RUSAGE
-    {"BLOGC_RUSAGE_CPU_TIME", blogc_rusage_cpu_time},
-    {"BLOGC_RUSAGE_MEMORY", blogc_rusage_memory},
+    {"BLOGC_RUSAGE_CPU_TIME", blogc_rusage_inject},
+    {"BLOGC_RUSAGE_MEMORY", blogc_rusage_inject},
 #endif
 
     {NULL, NULL},
@@ -39,11 +39,8 @@ blogc_funcvars_lookup(const char *name, bc_trie_t *global)
 
     for (size_t i = 0; funcs[i].variable != NULL; i++) {
         if (0 == strcmp(name, funcs[i].variable)) {
-            char *val = funcs[i].func();
-            if (val == NULL)
-                return NULL;
-            bc_trie_insert(global, name, bc_strdup(val));
-            return val;
+            funcs[i].func(global);
+            return bc_strdup(bc_trie_lookup(global, name));
         }
     }
 
diff --git a/src/blogc/funcvars.h b/src/blogc/funcvars.h
index d46266f..f554f8d 100644
--- a/src/blogc/funcvars.h
+++ b/src/blogc/funcvars.h
@@ -12,7 +12,7 @@
 #include <stdbool.h>
 #include "../common/utils.h"
 
-typedef char* (*blogc_funcvars_func_t) (void);
+typedef void (*blogc_funcvars_func_t) (bc_trie_t*);
 
 char* blogc_funcvars_lookup(const char *name, bc_trie_t *global);
 
diff --git a/src/blogc/rusage.c b/src/blogc/rusage.c
index 972ae4f..7c04db3 100644
--- a/src/blogc/rusage.c
+++ b/src/blogc/rusage.c
@@ -18,24 +18,28 @@
 #include <sys/resource.h>
 #endif /* HAVE_SYS_RESOURCE_H */
 
+#include <stdlib.h>
 #include "../common/utils.h"
 #include "rusage.h"
 
-// FIXME: optimize to use a single syscall for both cpu time and memory?
 
-
-long long
-blogc_rusage_get_cpu_time(void)
+blogc_rusage_t*
+blogc_rusage_get(void)
 {
 #ifndef HAVE_RUSAGE
-    return 0;
+    return NULL;
 #else
     struct rusage usage;
     if (0 != getrusage(RUSAGE_SELF, &usage))
-        return 0;
-    return (
+        return NULL;
+
+    blogc_rusage_t *rv = bc_malloc(sizeof(blogc_rusage_t));
+    rv->cpu_time = (
         (usage.ru_utime.tv_sec * 1000000) + usage.ru_utime.tv_usec +
         (usage.ru_stime.tv_sec * 1000000) + usage.ru_stime.tv_usec);
+    rv->memory = usage.ru_maxrss;
+
+    return rv;
 #endif
 }
 
@@ -55,27 +59,6 @@ blogc_rusage_format_cpu_time(long long time)
 }
 
 
-char*
-blogc_rusage_cpu_time(void)
-{
-    return blogc_rusage_format_cpu_time(blogc_rusage_get_cpu_time());
-}
-
-
-long
-blogc_rusage_get_memory(void)
-{
-#ifndef HAVE_RUSAGE
-    return 0;
-#else
-    struct rusage usage;
-    if (0 != getrusage(RUSAGE_SELF, &usage))
-        return 0;
-    return usage.ru_maxrss;
-#endif
-}
-
-
 char*
 blogc_rusage_format_memory(long mem)
 {
@@ -87,8 +70,17 @@ blogc_rusage_format_memory(long mem)
 }
 
 
-char*
-blogc_rusage_memory(void)
+void
+blogc_rusage_inject(bc_trie_t *global)
 {
-    return blogc_rusage_format_memory(blogc_rusage_get_memory());
+    blogc_rusage_t *usage = blogc_rusage_get();
+    if (usage == NULL)
+        return;
+
+    bc_trie_insert(global, "BLOGC_RUSAGE_CPU_TIME",
+        blogc_rusage_format_cpu_time(usage->cpu_time));
+    bc_trie_insert(global, "BLOGC_RUSAGE_MEMORY",
+        blogc_rusage_format_memory(usage->memory));
+
+    free(usage);
 }
diff --git a/src/blogc/rusage.h b/src/blogc/rusage.h
index 4065552..3441630 100644
--- a/src/blogc/rusage.h
+++ b/src/blogc/rusage.h
@@ -17,19 +17,18 @@
 #define HAVE_RUSAGE 1
 #endif /* HAVE_SYS_RESOURCE_H */
 
+#include "../common/utils.h"
+
 typedef struct {
     long long cpu_time;  // in microseconds
     long memory;         // in kilobytes
 } blogc_rusage_t;
 
 blogc_rusage_t* blogc_rusage_get(void);
-long long blogc_rusage_get_cpu_time(void);  // in microseconds
-long blogc_rusage_get_memory(void);         // in kilobytes
 
 char* blogc_rusage_format_cpu_time(long long time);
 char* blogc_rusage_format_memory(long mem);
 
-char* blogc_rusage_cpu_time(void);
-char* blogc_rusage_memory(void);
+void blogc_rusage_inject(bc_trie_t *global);
 
 #endif /* ___RUSAGE_H */
-- 
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