From: Nicholas Clark <nick@ccl4.org>
Date: Tue, 10 May 2005 11:03:49 +0000 (+0000)
Subject: Experiment with using the ptr_table code to hold the seen hash
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=ab923da19db4ee1bc3a2e308f5fef9d92ee4928a;p=p5sagit%2Fp5-mst-13.2.git
Experiment with using the ptr_table code to hold the seen hash
p4raw-id: //depot/perl@24436
---
diff --git a/ext/Storable/Storable.xs b/ext/Storable/Storable.xs
index 09992f2..aaf62e2 100644
--- a/ext/Storable/Storable.xs
+++ b/ext/Storable/Storable.xs
@@ -294,6 +294,10 @@ typedef unsigned long stag_t; /* Used by pre-0.6 binary format */
#define HAS_HASH_KEY_FLAGS
#endif
+#ifdef ptr_table_new
+#define USE_PTR_TABLE
+#endif
+
/*
* Fields s_tainted and s_dirty are prefixed with s_ because Perl's include
* files remap tainted and dirty when threading is enabled. That's bad for
@@ -304,7 +308,16 @@ struct stcxt;
typedef struct stcxt {
int entry; /* flags recursion */
int optype; /* type of traversal operation */
- HV *hseen; /* which objects have been seen, store time */
+ /* which objects have been seen, store time.
+ tags are numbers, which are cast to (SV *) and stored directly */
+#ifdef USE_PTR_TABLE
+ /* use pseen if we have ptr_tables. We have to store tag+1, because
+ tag numbers start at 0, and we can't store (SV *) 0 in a ptr_table
+ without it being confused for a fetch lookup failure. */
+ struct ptr_tbl *pseen;
+ /* Still need hseen for the 0.6 file format code. */
+#endif
+ HV *hseen;
AV *hook_seen; /* which SVs were returned by STORABLE_freeze() */
AV *aseen; /* which objects have been seen, retrieve time */
IV where_is_undef; /* index in aseen of PL_sv_undef */
@@ -1227,9 +1240,13 @@ static void init_store_context(
* those optimizations increase the throughput by 12%.
*/
+#ifdef USE_PTR_TABLE
+ cxt->pseen = ptr_table_new();
+ cxt->hseen = 0;
+#else
cxt->hseen = newHV(); /* Table where seen objects are stored */
HvSHAREKEYS_off(cxt->hseen);
-
+#endif
/*
* The following does not work well with perl5.004_04, and causes
* a core dump later on, in a completely unrelated spot, which
@@ -1248,8 +1265,10 @@ static void init_store_context(
*/
#if PERL_VERSION >= 5
#define HBUCKETS 4096 /* Buckets for %hseen */
+#ifndef USE_PTR_TABLE
HvMAX(cxt->hseen) = HBUCKETS - 1; /* keys %hseen = $HBUCKETS; */
#endif
+#endif
/*
* The `hclass' hash uses the same settings as `hseen' above, but it is
@@ -1303,11 +1322,13 @@ static void clean_store_context(pTHX_ stcxt_t *cxt)
* Insert real values into hashes where we stored faked pointers.
*/
+#ifndef USE_PTR_TABLE
if (cxt->hseen) {
hv_iterinit(cxt->hseen);
while ((he = hv_iternext(cxt->hseen))) /* Extra () for -Wall, grr.. */
HeVAL(he) = &PL_sv_undef;
}
+#endif
if (cxt->hclass) {
hv_iterinit(cxt->hclass);
@@ -1325,12 +1346,21 @@ static void clean_store_context(pTHX_ stcxt_t *cxt)
* -- RAM, 20/12/2000
*/
+#ifdef USE_PTR_TABLE
+ if (cxt->pseen) {
+ struct ptr_tbl *pseen = cxt->pseen;
+ cxt->pseen = 0;
+ ptr_table_free(pseen);
+ }
+ assert(!cxt->hseen);
+#else
if (cxt->hseen) {
HV *hseen = cxt->hseen;
cxt->hseen = 0;
hv_undef(hseen);
sv_free((SV *) hseen);
}
+#endif
if (cxt->hclass) {
HV *hclass = cxt->hclass;
@@ -1384,6 +1414,10 @@ static void init_retrieve_context(pTHX_ stcxt_t *cxt, int optype, int is_tainted
cxt->hook = newHV(); /* Caches STORABLE_thaw */
+#ifdef USE_PTR_TABLE
+ cxt->pseen = 0;
+#endif
+
/*
* If retrieving an old binary version, the cxt->retrieve_vtbl variable
* was set to sv_old_retrieve. We'll need a hash table to keep track of
@@ -2928,9 +2962,14 @@ static int store_hook(
*/
for (i = 1; i < count; i++) {
+#ifdef USE_PTR_TABLE
+ char *fake_tag;
+#else
SV **svh;
+#endif
SV *rsv = ary[i];
SV *xsv;
+ SV *tag;
AV *av_hook = cxt->hook_seen;
if (!SvROK(rsv))
@@ -2942,9 +2981,18 @@ static int store_hook(
* Look in hseen and see if we have a tag already.
* Serialize entry if not done already, and get its tag.
*/
-
+
+#ifdef USE_PTR_TABLE
+ /* Fakery needed because ptr_table_fetch returns zero for a
+ failure, whereas the existing code assumes that it can
+ safely store a tag zero. So for ptr_tables we store tag+1
+ */
+ if (fake_tag = ptr_table_fetch(cxt->pseen, xsv))
+ goto sv_seen; /* Avoid moving code too far to the right */
+#else
if ((svh = hv_fetch(cxt->hseen, (char *) &xsv, sizeof(xsv), FALSE)))
goto sv_seen; /* Avoid moving code too far to the right */
+#endif
TRACEME(("listed object %d at 0x%"UVxf" is unknown", i-1, PTR2UV(xsv)));
@@ -2971,10 +3019,15 @@ static int store_hook(
if ((ret = store(aTHX_ cxt, xsv))) /* Given by hook for us to store */
return ret;
+#ifdef USE_PTR_TABLE
+ fake_tag = ptr_table_fetch(cxt->pseen, xsv);
+ if (!sv)
+ CROAK(("Could not serialize item #%d from hook in %s", i, classname));
+#else
svh = hv_fetch(cxt->hseen, (char *) &xsv, sizeof(xsv), FALSE);
if (!svh)
CROAK(("Could not serialize item #%d from hook in %s", i, classname));
-
+#endif
/*
* It was the first time we serialized `xsv'.
*
@@ -3004,9 +3057,14 @@ static int store_hook(
* Replace entry with its tag (not a real SV, so no refcnt increment)
*/
- ary[i] = *svh;
+#ifdef USE_PTR_TABLE
+ tag = (SV *)--fake_tag;
+#else
+ tag = *svh;
+#endif
+ ary[i] = tag
TRACEME(("listed object %d at 0x%"UVxf" is tag #%"UVuf,
- i-1, PTR2UV(xsv), PTR2UV(*svh)));
+ i-1, PTR2UV(xsv), PTR2UV(tag)));
}
/*
@@ -3371,7 +3429,11 @@ static int store(pTHX_ stcxt_t *cxt, SV *sv)
SV **svh;
int ret;
int type;
+#ifdef USE_PTR_TABLE
+ struct ptr_tbl *pseen = cxt->pseen;
+#else
HV *hseen = cxt->hseen;
+#endif
TRACEME(("store (0x%"UVxf")", PTR2UV(sv)));
@@ -3387,7 +3449,11 @@ static int store(pTHX_ stcxt_t *cxt, SV *sv)
* -- RAM, 14/09/1999
*/
+#ifdef USE_PTR_TABLE
+ svh = ptr_table_fetch(pseen, sv);
+#else
svh = hv_fetch(hseen, (char *) &sv, sizeof(sv), FALSE);
+#endif
if (svh) {
I32 tagval;
@@ -3421,7 +3487,11 @@ static int store(pTHX_ stcxt_t *cxt, SV *sv)
goto undef_special_case;
}
+#ifdef USE_PTR_TABLE
+ tagval = htonl(LOW_32BITS(((char *)svh)-1));
+#else
tagval = htonl(LOW_32BITS(*svh));
+#endif
TRACEME(("object 0x%"UVxf" seen as #%d", PTR2UV(sv), ntohl(tagval)));
@@ -3442,9 +3512,13 @@ static int store(pTHX_ stcxt_t *cxt, SV *sv)
*/
cxt->tagnum++;
+#ifdef USE_PTR_TABLE
+ ptr_table_store(pseen, sv, INT2PTR(SV*, 1 + cxt->tagnum));
+#else
if (!hv_store(hseen,
(char *) &sv, sizeof(sv), INT2PTR(SV*, cxt->tagnum), 0))
return -1;
+#endif
/*
* Store `sv' and everything beneath it, using appropriate routine.