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authorDave Barach <dave@barachs.net>2019-06-14 12:02:38 -0400
committerDave Barach <dave@barachs.net>2019-06-14 12:15:28 -0400
commit9c8ca8dd3197e40dfcb8bcecd95c10eeb56239ed (patch)
tree68400772b8c35b5cd2443c42a23a02d45c333b9b
parentb63dbc537c02b1978345744ab34765b2d75011a6 (diff)
vppinfra: optimize elog_string
Add a string hash to make sure that strings in the string table are unique. This optimization has been coded piecemeal in multiple places, we should have made the underlying function do the work years ago. Type: fix Change-Id: I5010fd4926b9b80ce3a168748f6de64e333ef498 Signed-off-by: Dave Barach <dave@barachs.net>
-rw-r--r--src/vppinfra/elog.c33
-rw-r--r--src/vppinfra/elog.h3
2 files changed, 31 insertions, 5 deletions
diff --git a/src/vppinfra/elog.c b/src/vppinfra/elog.c
index e28217cd590..19d86bb70c0 100644
--- a/src/vppinfra/elog.c
+++ b/src/vppinfra/elog.c
@@ -508,6 +508,7 @@ elog_init (elog_main_t * em, u32 n_events)
elog_track_register (em, &em->default_track);
elog_time_now (&em->init_time);
+ em->string_table_hash = hash_create_string (0, sizeof (uword));
}
/* Returns number of events in ring and start index. */
@@ -561,17 +562,39 @@ u32
elog_string (elog_main_t * em, char *fmt, ...)
{
u32 offset;
+ uword *p;
+ uword len;
va_list va;
elog_lock (em);
+ vec_reset_length (em->string_table_tmp);
va_start (va, fmt);
- offset = vec_len (em->string_table);
- em->string_table = (char *) va_format ((u8 *) em->string_table, fmt, &va);
+ em->string_table_tmp = va_format (em->string_table_tmp, fmt, &va);
va_end (va);
- /* Null terminate string if it is not already. */
- if (vec_end (em->string_table)[-1] != 0)
- vec_add1 (em->string_table, 0);
+ /* See if we already have this string in the string table */
+ p = hash_get_mem (em->string_table_hash, em->string_table_tmp);
+
+ /* We already have the string, so give the caller its offset */
+ if (p)
+ {
+ elog_unlock (em);
+ return (p[0]);
+ }
+
+ /* We don't, so add it. String table entries MUST be NULL terminated */
+ len = vec_len (em->string_table_tmp);
+ ASSERT (len > 0);
+ if (em->string_table_tmp[len - 1] != 0)
+ vec_add1 (em->string_table_tmp, 0);
+
+ offset = vec_len (em->string_table);
+ vec_append (em->string_table, em->string_table_tmp);
+
+ hash_set_mem (em->string_table_hash, em->string_table_tmp, offset);
+
+ /* We gave the key to the string table hash, so we can't reuse it! */
+ em->string_table_tmp = 0;
elog_unlock (em);
return offset;
diff --git a/src/vppinfra/elog.h b/src/vppinfra/elog.h
index 26352f7d608..3cd067ce707 100644
--- a/src/vppinfra/elog.h
+++ b/src/vppinfra/elog.h
@@ -53,6 +53,7 @@
#include <vppinfra/error.h> /* for ASSERT */
#include <vppinfra/serialize.h>
#include <vppinfra/time.h> /* for clib_cpu_time_now */
+#include <vppinfra/hash.h>
#include <vppinfra/mhash.h>
typedef struct
@@ -155,6 +156,8 @@ typedef struct
/** Events may refer to strings in string table. */
char *string_table;
+ uword *string_table_hash;
+ u8 *string_table_tmp;
/** Vector of tracks. */
elog_track_t *tracks;