Performance: disable event counting by default

[lttng-modules.git] / lib / ringbuffer / backend_internal.h

diff --git a/lib/ringbuffer/backend_internal.h b/lib/ringbuffer/backend_internal.h
index 442f357a4c40120aae2f06d897aee7a723f1cd56..fc5bec535c591b3d9487e555c0dbbbf2055f5dc9 100644 (file)
--- a/lib/ringbuffer/backend_internal.h
+++ b/lib/ringbuffer/backend_internal.h
@@ -1,19 +1,31 @@
-#ifndef _LINUX_RING_BUFFER_BACKEND_INTERNAL_H
-#define _LINUX_RING_BUFFER_BACKEND_INTERNAL_H
+#ifndef _LIB_RING_BUFFER_BACKEND_INTERNAL_H
+#define _LIB_RING_BUFFER_BACKEND_INTERNAL_H
 
 /*
- * linux/ringbuffer/backend_internal.h
- *
- * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * lib/ringbuffer/backend_internal.h
  *
  * Ring buffer backend (internal helpers).
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2008-2012 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 "../../wrapper/ringbuffer/config.h"
-#include "../../wrapper/ringbuffer/backend_types.h"
-#include "../../wrapper/ringbuffer/frontend_types.h"
+#include <wrapper/ringbuffer/config.h>
+#include <wrapper/ringbuffer/backend_types.h>
+#include <wrapper/ringbuffer/frontend_types.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
 
@@ -40,13 +52,19 @@ void lib_ring_buffer_backend_exit(void);
 
 extern void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb,
                                   size_t offset, const void *src, size_t len,
-                                  ssize_t pagecpy);
+                                  size_t pagecpy);
 extern void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb,
                                    size_t offset, int c, size_t len,
-                                   ssize_t pagecpy);
-extern void _lib_ring_buffer_copy_from_user(struct lib_ring_buffer_backend *bufb,
+                                   size_t pagecpy);
+extern void _lib_ring_buffer_strcpy(struct lib_ring_buffer_backend *bufb,
+                                  size_t offset, const char *src, size_t len,
+                                  size_t pagecpy, int pad);
+extern void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb,
                                            size_t offset, const void *src,
-                                           size_t len, ssize_t pagecpy);
+                                           size_t len, size_t pagecpy);
+extern void _lib_ring_buffer_strcpy_from_user_inatomic(struct lib_ring_buffer_backend *bufb,
+               size_t offset, const char __user *src, size_t len,
+               size_t pagecpy, int pad);
 
 /*
  * Subbuffer ID bits for overwrite mode. Need to fit within a single word to be
@@ -183,6 +201,11 @@ int subbuffer_id_check_index(const struct lib_ring_buffer_config *config,
                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 lib_ring_buffer_config *config,
                            struct lib_ring_buffer_backend *bufb,
@@ -193,6 +216,14 @@ void subbuffer_count_record(const struct lib_ring_buffer_config *config,
        sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
        v_inc(config, &bufb->array[sb_bindex]->records_commit);
 }
+#else /* LTTNG_RING_BUFFER_COUNT_EVENTS */
+static inline
+void subbuffer_count_record(const struct lib_ring_buffer_config *config,
+                           struct lib_ring_buffer_backend *bufb,
+                           unsigned long idx)
+{
+}
+#endif /* #else LTTNG_RING_BUFFER_COUNT_EVENTS */
 
 /*
  * Reader has exclusive subbuffer access for record consumption. No need to
@@ -226,9 +257,10 @@ 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(
@@ -290,6 +322,14 @@ unsigned long subbuffer_get_data_size(
        return pages->data_size;
 }
 
+static inline
+void subbuffer_inc_packet_count(const struct lib_ring_buffer_config *config,
+                               struct lib_ring_buffer_backend *bufb,
+                               unsigned long idx)
+{
+       bufb->buf_cnt[idx].seq_cnt++;
+}
+
 /**
  * lib_ring_buffer_clear_noref - Clear the noref subbuffer flag, called by
  *                               writer.
@@ -422,15 +462,17 @@ do {                                                              \
 } while (0)
 
 /*
- * We use __copy_from_user to copy userspace data since we already
+ * We use __copy_from_user_inatomic to copy userspace data since we already
  * did the access_ok for the whole range.
+ *
+ * Return 0 if OK, nonzero on error.
  */
 static inline
-unsigned long lib_ring_buffer_do_copy_from_user(void *dest,
+unsigned long lib_ring_buffer_do_copy_from_user_inatomic(void *dest,
                                                const void __user *src,
                                                unsigned long len)
 {
-       return __copy_from_user(dest, src, len);
+       return __copy_from_user_inatomic(dest, src, len);
 }
 
 /*
@@ -446,4 +488,4 @@ void lib_ring_buffer_do_memset(char *dest, int c,
                dest[i] = c;
 }
 
-#endif /* _LINUX_RING_BUFFER_BACKEND_INTERNAL_H */
+#endif /* _LIB_RING_BUFFER_BACKEND_INTERNAL_H */