Vsync proposal

bin/varnishd/Makefile.am

@@ -53,6 +53,7 @@ varnishd_SOURCES = \
 	cache/cache_vrt_var.c \
 	cache/cache_vrt_vcl.c \
 	cache/cache_vrt_vmod.c \
+	cache/cache_vsync.c \
 	cache/cache_wrk.c \
 	cache/cache_ws_common.c \
 	common/common_vsc.c \

bin/varnishd/cache/cache_main.c

@@ -402,6 +402,7 @@ child_main(int sigmagic, size_t altstksz)
 	VSM_Init();	/* First, LCK needs it. */
 
 	LCK_Init();	/* Second, locking */
+	SYNC_Init();
 
 	Lck_New(&vxid_lock, lck_vxid);
 

bin/varnishd/cache/cache_varnishd.h

@@ -604,3 +604,6 @@ void SMP_Ready(void);
 		if (DO_DEBUG(debug_bit))			\
 			WRK_Log(SLT_Debug, __VA_ARGS__);	\
 	} while (0)
+
+/* cache_vsync.c */
+void SYNC_Init(void);

bin/varnishd/cache/cache_vsync.c

@@ -0,0 +1,122 @@
+/*-
+ * Copyright (c) 2024 Varnish Software AS
+ * All rights reserved.
+ *
+ * Author: Stephane Cance <[email protected]>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <errno.h>
+
+#include "cache_varnishd.h"
+
+#include "vtim.h"
+#include "vsync.h"
+
+#include "VSC_lck.h"
+#include "VSC_cond.h"
+
+static void
+mtx_sync_evt(const char *func, const char *file,
+    int line, enum vsync_mtx_event evt, struct VSC_lck *vsc)
+{
+	AN(vsc);
+
+	(void)func;
+	(void)line;
+	(void)file;
+
+
+	switch (evt) {
+	case VSYNC_MTX_INIT:
+		__sync_fetch_and_add(&vsc->creat, 1);
+		break;
+	case VSYNC_MTX_FINI:
+		__sync_fetch_and_add(&vsc->destroy, 1);
+		break;
+	case VSYNC_MTX_LOCK:
+		__sync_fetch_and_add(&vsc->locks, 1);
+		break;
+	case VSYNC_MTX_UNLOCK:
+		break;
+	}
+}
+
+static void
+cond_sync_evt(const char *func, const char *file, int line,
+	enum vsync_cond_event evt, struct VSC_cond *vsc_cond,
+	struct VSC_lck *vsc_mtx, double *start_atp)
+{
+	vtim_mono now;
+
+	AN(vsc_cond);
+
+	(void)func;
+	(void)line;
+	(void)file;
+	(void)vsc_mtx;
+
+	switch (evt) {
+	case VSYNC_COND_INIT:
+		__sync_fetch_and_add(&vsc_cond->init, 1);
+		AZ(start_atp);
+		break;
+	case VSYNC_COND_FINI:
+		__sync_fetch_and_add(&vsc_cond->fini, 1);
+		AZ(start_atp);
+		break;
+	case VSYNC_COND_SIGNAL:
+		__sync_fetch_and_add(&vsc_cond->signal, 1);
+		AZ(start_atp);
+		break;
+	case VSYNC_COND_BROADCAST:
+		__sync_fetch_and_add(&vsc_cond->broadcast, 1);
+		AZ(start_atp);
+		break;
+	case VSYNC_COND_WAIT_START:
+		__sync_fetch_and_add(&vsc_cond->waiting, 1);
+		AN(start_atp);
+		*start_atp = VTIM_mono();
+		break;
+	case VSYNC_COND_WAIT_END:
+		AN(start_atp);
+		now = VTIM_mono();
+		assert(now > *start_atp);
+
+		__sync_fetch_and_sub(&vsc_cond->waiting, 1);
+		__sync_fetch_and_add(&vsc_cond->waits, 1);
+		__sync_fetch_and_add(&vsc_cond->wait_duration_ns,
+		    (uint64_t)((now - *start_atp) * 1e9));
+		break;
+	}
+}
+
+void
+SYNC_Init(void)
+{
+	VSYNC_mtx_event_func = mtx_sync_evt;
+	VSYNC_cond_event_func = cond_sync_evt;
+}

configure.ac

@@ -229,6 +229,7 @@ save_LIBS="${LIBS}"
 LIBS="${PTHREAD_LIBS}"
 AC_CHECK_FUNCS([pthread_mutex_isowned_np])
 AC_CHECK_FUNCS([pthread_getattr_np])
+AC_CHECK_FUNCS([pthread_condattr_setclock])
 LIBS="${save_LIBS}"
 
 AC_CHECK_DECL([__SUNPRO_C], [SUNCC="yes"], [SUNCC="no"])

include/Makefile.am

@@ -79,6 +79,7 @@ nobase_pkginclude_HEADERS += \
 	vsa.h \
 	vsb.h \
 	vsha256.h \
+	vsync.h \
 	vtcp.h \
 	vte.h \
 	vtim.h \

include/vdef.h

@@ -44,6 +44,8 @@
 #endif
 #define VDEF_H_INCLUDED
 
+#include <math.h>
+
 /* Safe printf into a fixed-size buffer */
 #define bprintf(buf, fmt, ...)						\
 	do {								\