Performance: disable event counting by default

[lttng-ust.git] / libringbuffer / backend_internal.h

diff --git a/libringbuffer/backend_internal.h b/libringbuffer/backend_internal.h
index c9ed81be0e5b5c559ba8de23846a6052ecc8ddea..7bd5c738936084a0ed84fec4fa822a44211812f7 100644 (file)
--- a/libringbuffer/backend_internal.h
+++ b/libringbuffer/backend_internal.h
@@ -1,14 +1,26 @@
-#ifndef _LINUX_RING_BUFFER_BACKEND_INTERNAL_H
-#define _LINUX_RING_BUFFER_BACKEND_INTERNAL_H
+#ifndef _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H
+#define _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H
 
 /*
- * linux/ringbuffer/backend_internal.h
- *
- * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * libringbuffer/backend_internal.h
  *
  * Ring buffer backend (internal helpers).
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This 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; only
+ * version 2.1 of the License.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <unistd.h>
@@ -33,7 +45,8 @@ int channel_backend_init(struct channel_backend *chanb,
                         const char *name,
                         const struct lttng_ust_lib_ring_buffer_config *config,
                         size_t subbuf_size,
-                        size_t num_subbuf, struct lttng_ust_shm_handle *handle);
+                        size_t num_subbuf, struct lttng_ust_shm_handle *handle,
+                        const int *stream_fds);
 void channel_backend_free(struct channel_backend *chanb,
                          struct lttng_ust_shm_handle *handle);
 
@@ -183,6 +196,11 @@ int subbuffer_id_check_index(const struct lttng_ust_lib_ring_buffer_config *conf
                return 0;
 }
 
+/*
+ * The ring buffer can count events recorded and overwritten per buffer,
+ * but it is disabled by default due to its performance overhead.
+ */
+#ifdef LTTNG_RING_BUFFER_COUNT_EVENTS
 static inline
 void subbuffer_count_record(const struct lttng_ust_lib_ring_buffer_config *config,
                            struct lttng_ust_lib_ring_buffer_backend *bufb,
@@ -193,6 +211,14 @@ void subbuffer_count_record(const struct lttng_ust_lib_ring_buffer_config *confi
        sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id);
        v_inc(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_commit);
 }
+#else /* LTTNG_RING_BUFFER_COUNT_EVENTS */
+static inline
+void subbuffer_count_record(const struct lttng_ust_lib_ring_buffer_config *config,
+                           struct lttng_ust_lib_ring_buffer_backend *bufb,
+                           unsigned long idx, struct lttng_ust_shm_handle *handle)
+{
+}
+#endif /* #else LTTNG_RING_BUFFER_COUNT_EVENTS */
 
 /*
  * Reader has exclusive subbuffer access for record consumption. No need to
@@ -228,9 +254,10 @@ unsigned long subbuffer_get_records_count(
 
 /*
  * Must be executed at subbuffer delivery when the writer has _exclusive_
- * subbuffer access. See ring_buffer_check_deliver() for details.
- * ring_buffer_get_records_count() must be called to get the records count
- * before this function, because it resets the records_commit count.
+ * subbuffer access. See lib_ring_buffer_check_deliver() for details.
+ * lib_ring_buffer_get_records_count() must be called to get the records
+ * count before this function, because it resets the records_commit
+ * count.
  */
 static inline
 unsigned long subbuffer_count_records_overrun(
@@ -296,6 +323,14 @@ unsigned long subbuffer_get_data_size(
        return shmp(handle, pages->shmp)->data_size;
 }
 
+static inline
+void subbuffer_inc_packet_count(const struct lttng_ust_lib_ring_buffer_config *config,
+               struct lttng_ust_lib_ring_buffer_backend *bufb,
+               unsigned long idx, struct lttng_ust_shm_handle *handle)
+{
+       shmp_index(handle, bufb->buf_cnt, idx)->seq_cnt++;
+}
+
 /**
  * lib_ring_buffer_clear_noref - Clear the noref subbuffer flag, called by
  *                               writer.
@@ -434,6 +469,18 @@ do {                                                               \
                inline_memcpy(dest, src, __len);                \
 } while (0)
 
+/*
+ * write len bytes to dest with c
+ */
+static inline
+void lib_ring_buffer_do_memset(char *dest, int c, unsigned long len)
+{
+       unsigned long i;
+
+       for (i = 0; i < len; i++)
+               dest[i] = c;
+}
+
 /* arch-agnostic implementation */
 
 static inline int lttng_ust_fls(unsigned int x)
@@ -459,7 +506,7 @@ static inline int lttng_ust_fls(unsigned int x)
                r -= 2;
        }
        if (!(x & 0x80000000U)) {
-               x <<= 1;
+               /* No need to bit shift on last operation */
                r -= 1;
        }
        return r;
@@ -475,20 +522,4 @@ static inline int get_count_order(unsigned int count)
        return order;
 }
 
-static inline
-unsigned int hweight32(unsigned int value)
-{
-       unsigned int r;
-
-       r = value;
-       r = r - ((r >> 1) & 0x55555555);
-       r = (r & 0x33333333) + ((r >> 2) & 0x33333333);
-       r += r >> 4;
-       r &= 0x0F0F0F0F;
-       r += r >> 8;
-       r += r >> 16;
-       r &= 0x000000FF;
-       return r;
-}
-
-#endif /* _LINUX_RING_BUFFER_BACKEND_INTERNAL_H */
+#endif /* _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H */