improved statistics-gathering subsystem

... well, actually this is a first real implementation of this subsystem.
I have added a counter registry, a way to access the countres (as readable
string) and a way to define and maintem them. Also, module impstats has
been updated to utilize the new system. Finally, I added some counters. I
hope that this sets the baseline for useful future enhancements.

1 files changed, 124 insertions, 0 deletions

diff --git a/runtime/statsobj.h b/runtime/statsobj.h
new file mode 100644
index 00000000..1ab02182
--- /dev/null
+++ b/runtime/statsobj.h
@@ -0,0 +1,124 @@
+/* The statsobj object.
+ *
+ * Copyright 2010 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * The rsyslog runtime library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * The rsyslog runtime library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the rsyslog runtime library.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution.
+ */
+#ifndef INCLUDED_STATSOBJ_H
+#define INCLUDED_STATSOBJ_H
+
+#include "atomic.h"
+
+/* The following data item is somewhat dirty, in that it does not follow
+ * our usual object calling conventions. However, much like with "Debug", we
+ * do this to gain speed. If we finally come to a platform that does not
+ * provide resolution of names for dynamically loaded modules, we need to find
+ * a work-around, but until then, we use the direct access.
+ * If set to 0, statistics are not gathered, otherwise they are.
+ */
+extern int GatherStats;
+
+/* our basic counter type -- need 32 bit on 32 bit platform. 
+ * IMPORTANT: this type *MUST* be supported by atomic instructions!
+ */
+typedef uint64 intctr_t;
+
+/* counter types */
+typedef enum statsCtrType_e {
+	ctrType_IntCtr,
+	ctrType_Int
+} statsCtrType_t;
+
+
+/* helper entity, the counter */
+typedef struct ctr_s {
+	uchar *name;
+	statsCtrType_t ctrType;
+	union {
+		intctr_t *pIntCtr;
+		int *pInt;
+	} val;
+	struct ctr_s *next, *prev;
+} ctr_t;
+
+/* the statsobj object */
+struct statsobj_s {
+	BEGINobjInstance;		/* Data to implement generic object - MUST be the first data element! */
+	uchar *name;
+	pthread_mutex_t mutCtr;		/* to guard counter linked-list ops */
+	ctr_t *ctrRoot;			/* doubly-linked list of statsobj counters */
+	ctr_t *ctrLast;
+	/* used to link ourselves together */
+	statsobj_t *prev;
+	statsobj_t *next;
+};
+
+
+/* interfaces */
+BEGINinterface(statsobj) /* name must also be changed in ENDinterface macro! */
+	INTERFACEObjDebugPrint(statsobj);
+	rsRetVal (*Construct)(statsobj_t **ppThis);
+	rsRetVal (*ConstructFinalize)(statsobj_t *pThis);
+	rsRetVal (*Destruct)(statsobj_t **ppThis);
+	rsRetVal (*SetName)(statsobj_t *pThis, uchar *name);
+	rsRetVal (*GetStatsLine)(statsobj_t *pThis, cstr_t **ppcstr);
+	rsRetVal (*GetAllStatsLines)(rsRetVal(*cb)(void*, cstr_t*), void *usrptr);
+	rsRetVal (*AddCounter)(statsobj_t *pThis, uchar *ctrName, statsCtrType_t ctrType, void *pCtr);
+	rsRetVal (*EnableStats)(void);
+ENDinterface(statsobj)
+#define statsobjCURR_IF_VERSION 1 /* increment whenever you change the interface structure! */
+
+
+/* prototypes */
+PROTOTYPEObj(statsobj);
+
+
+/* macros to handle stats counters
+ * These are to be used by "counter providers". Note that we MUST
+ * specify the mutex name, even though at first it looks like it
+ * could be automatically be generated via e.g. "mut##ctr". 
+ * Unfortunately, this does not work if counter is e.g. "pThis->ctr".
+ * So we decided, for clarity, to always insist on specifying the mutex
+ * name (after all, it's just a few more keystrokes...).
+ */
+#define STATSCOUNTER_DEF(ctr, mut) \
+	intctr_t ctr; \
+	DEF_ATOMIC_HELPER_MUT(mut)
+
+#define STATSCOUNTER_INIT(ctr, mut) \
+	INIT_ATOMIC_HELPER_MUT(mut); \
+	ctr = 0;
+
+#define STATSCOUNTER_INC(ctr, mut) \
+	if(GatherStats) \
+		ATOMIC_INC(&ctr, mut);
+
+#define STATSCOUNTER_DEC(ctr, mut) \
+	if(GatherStats) \
+		ATOMIC_DEC(&ctr, mut);
+
+/* the next macro works only if the variable is already guarded
+ * by mutex (or the users risks a wrong result). It is assumed 
+ * that there are not concurrent operations that modify the counter.
+ */
+#define STATSCOUNTER_SETMAX_NOMUT(ctr, newmax) \
+	if(GatherStats && ((newmax) > (ctr))) \
+		ctr = newmax;
+
+#endif /* #ifndef INCLUDED_STATSOBJ_H */