From 8f0b9a80d1c605d73ec4e663d099aa87b0f95e87 Mon Sep 17 00:00:00 2001
From: Per Hedbor <ph@opera.com>
Date: Thu, 19 Jun 2014 15:43:37 +0200
Subject: [PATCH] Made short string size dependent on size of struct
pike_string, aim for 25% wasted space on average
---
src/stralloc.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/src/stralloc.c b/src/stralloc.c
index 067c56844f..262c3f7d56 100644
--- a/src/stralloc.c
+++ b/src/stralloc.c
@@ -621,11 +621,16 @@ struct pike_string_hdr {
#define SHORT_STRING_BLOCK 256
-#define SHORT_STRING_THRESHOLD 15
+
+/* breakpoint at 50% overhead. This doubles the size of short strings
+ on 64-bit systems, but it only increases memory usage for short
+ strings, on average, by 25% or so. */
+
+#define SHORT_STRING_THRESHOLD ((ptrdiff_t)sizeof(struct pike_string_hdr)-1)
struct short_pike_string0 {
PIKE_STRING_CONTENTS;
- p_wchar0 str[SHORT_STRING_THRESHOLD+1];
+ p_wchar0 str[sizeof(struct pike_string_hdr)];
};
static struct block_allocator string_allocator = BA_INIT(sizeof(struct short_pike_string0), SHORT_STRING_BLOCK);
@@ -658,9 +663,6 @@ PMOD_EXPORT struct pike_string *debug_begin_shared_string(size_t len)
t=xalloc(len + 1 + sizeof(struct pike_string_hdr));
t->flags = STRING_NOT_HASHED | STRING_NOT_SHARED;
}
-#ifdef ATOMIC_SVALUE
- t->ref_type = T_STRING;
-#endif
t->refs = 0;
add_ref(t); /* For DMALLOC */
t->str[len]=0;
@@ -773,9 +775,6 @@ PMOD_EXPORT struct pike_string *debug_begin_wide_shared_string(size_t len, int s
t=xalloc(((len + 1)<<shift) + sizeof(struct pike_string_hdr));
t->flags = STRING_NOT_HASHED|STRING_NOT_SHARED;
}
-#ifdef ATOMIC_SVALUE
- t->ref_type = T_STRING;
-#endif
t->refs = 0;
add_ref(t); /* For DMALLOC */
t->len=len;
--
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