Commit a742d3a9 authored by Stefan Reif's avatar Stefan Reif
Browse files

Make XLap opt-in 

- Make X-Lap disabled by default
- Enable X-Lap if the macro XLAP is defined
parent 53cce0dd

xlap.c

+1 −0
Original line number Diff line number Diff line 
#define XLAP

#include "xlap.h"



#include <stdatomic.h>

xlap.h

+100 −39
Original line number Diff line number Diff line
@@ -81,17 +81,25 @@ typedef struct XlapTimestampTableRow { 
/*

 * Table that stores timestamp table rows

 */

#ifdef XLAP

	typedef struct XlapTimestampTable {

		XlapTimestampTableRow rows[TS_ROWS];

	} XlapTimestampTable;

#else /* XLAP */

	typedef char XlapTimestampTable;

#endif



/*

 * Dummy data structure to store a single timestamp table row.

 */

#ifdef XLAP

	typedef struct XlapTimestampPlaceholder {

		_Atomic(XlapTimestampTable *) tstable[1];

		XlapTimestampTableRow rows[1];

	} XlapTimestampPlaceholder;

#else /* XLAP */

	typedef char XlapTimestampPlaceholder;

#endif



/*

 * update the clock value of a timestamp
@@ -99,9 +107,19 @@ typedef struct XlapTimestampPlaceholder { 
 * This macro will cause a SIGSEGV if the application does not install a

 * timestamp table to the socket.

 */

#ifdef XLAP

#	define XlapTimeStampClock(sck, kind, seqno, id) do { \

			clock_gettime(CLOCK_MONOTONIC, &atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire)->rows[(seqno) % TS_ROWS].time[ts_##id].actual.t); \

	} while (0);

		} while (0)

#else /* XLAP */

#	define XlapTimeStampClock(sck, kind, seqno, id) do { \

			(void) (sck); \

			(void) (kind); \

			(void) (seqno); \

			(void) (ts_##id); \

		} while (0)

#endif





/*

 * update the cycle value of a timestamp
@@ -109,42 +127,76 @@ typedef struct XlapTimestampPlaceholder { 
 * This macro will cause a SIGSEGV if the application does not install a

 * timestamp table to the socket.

 */

#ifdef XLAP

#	define XlapTimeStampCycle(sck, kind, seqno, id) do { \

			atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire)->rows[(seqno) % TS_ROWS].time[ts_##id].actual.c = __builtin_ia32_rdtsc(); \

	} while (0);

		} while (0)

#else /* XLAP */

#	define XlapTimeStampCycle(sck, kind, seqno, id) do { \

			(void) (sck); \

			(void) (kind); \

			(void) (seqno); \

			(void) (ts_##id); \

		} while (0)

#endif





/*

 * install a time stamp table to a socket

 */

#ifdef XLAP

#	define XlapTimestampTableInstall(sck, kind, tstp) do { \

			XlapTimestampTable *__tstp = (tstp); \

			memset(__tstp, 0, sizeof(XlapTimestampTable)); \

			atomic_store_explicit(&(sck)->tstable[kind], __tstp, memory_order_release); \

		} while (0)

#else /* XLAP */

#	define XlapTimestampTableInstall(sck, kind, tstp) do { \

			(void) (sck); \

			(void) (kind); \

			(void) (tstp); \

		} while (0)

#endif





/*

 * print a timestamp dump header

 */

#ifdef XLAP

	extern void XlapTimestampTableDumpHeader(FILE *);

#else

#	define XlapTimestampTableDumpHeader(f) do { \

			(void) (f); \

		} while (0)

#endif



/*

 * dump a timestamp table

 */

#ifdef XLAP

	extern void XlapTimestampTableDump(FILE *, XlapTimestampPacketKind, XlapTimestampTable *);



/*

 * use a specific timestamp table

 */

extern void XlapTimestampTableUse(XlapTimestampTable *);

#else

#	define XlapTimestampTableDump(f, k, t) do { \

			(void) (f); \

			(void) (k); \

			(void) (t); \

		} while (0)

#endif



/*

 * intialize a timestamp table placeholder

 */

#ifdef XLAP

#	define XlapTimestampPlaceholderInitialize(ph) do { \

			XlapTimestampPlaceholder *__ph = (ph); \

			atomic_store_explicit(&__ph->tstable[0], (XlapTimestampTable *) &__ph->rows, memory_order_release); \

			memset(&__ph->rows, 0x0, sizeof(XlapTimestampTableRow)); \

	} while (0);

		} while (0)

#else

#	define XlapTimestampPlaceholderInitialize(ph) do { \

			(void) (ph); \

		} while (0)

#endif



/*

 * copy a timestamp table placeholder into an actual timestamp table
@@ -152,6 +204,7 @@ extern void XlapTimestampTableUse(XlapTimestampTable *); 
 * Since every timestamp is taken at most once, either the timestamptable or

 * the placeholder value must be zero (for each timestamp).

 */

#ifdef XLAP

#	define XlapTimestampPlaceholderUse(sck, kind, seqno, ph) do { \

			XlapTimestampPlaceholder *__ph = (ph); \

			XlapTimestampTable       *__ts = atomic_load_explicit(&(sck)->tstable[kind], memory_order_acquire); \
@@ -161,5 +214,13 @@ extern void XlapTimestampTableUse(XlapTimestampTable *); 
				__ts->rows[seqno % TS_ROWS].time[__t].actual.c         += __ph->rows[0].time[__t].actual.c; \

			} \

		} while (0)

#else

#	define XlapTimestampPlaceholderUse(sck, kind, seqno, ph) do { \

			(void) (sck); \

			(void) (kind); \

			(void) (seqno); \

			(void) (ph); \

		} while (0)

#endif



#endif // XLAP_H