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[release/9.0-staging] [mono] Switch generic instance cache back to GHashTable; improve ginst hash function #113316

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Merged
merged 2 commits into from
Mar 10, 2025
Merged

[release/9.0-staging] [mono] Switch generic instance cache back to GHashTable; improve ginst hash function #113316

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c4af094
Switch generic instance cache back to GHashTable
kg Mar 8, 2025
7583a35
Replace mono_metadata_generic_inst_hash with a MurmurHash3 variant
kg Mar 8, 2025
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3 changes: 2 additions & 1 deletion src/mono/mono/metadata/loader-internals.h
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Original file line number Diff line number Diff line change
Expand Up @@ -175,7 +175,8 @@ struct _MonoMemoryManager {
MonoAssemblyLoadContext **alcs;

// Generic-specific caches
dn_simdhash_ght_t *ginst_cache, *gmethod_cache, *gsignature_cache;
GHashTable *ginst_cache;
dn_simdhash_ght_t *gmethod_cache, *gsignature_cache;
MonoConcurrentHashTable *gclass_cache;

/* mirror caches of ones already on MonoImage. These ones contain generics */
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2 changes: 1 addition & 1 deletion src/mono/mono/metadata/memory-manager.c
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Expand Up @@ -238,7 +238,7 @@ memory_manager_delete (MonoMemoryManager *memory_manager, gboolean debug_unload)
MonoMemoryManager *mm = memory_manager;
if (mm->gclass_cache)
mono_conc_hashtable_destroy (mm->gclass_cache);
free_simdhash (&mm->ginst_cache);
free_hash (&mm->ginst_cache);
free_simdhash (&mm->gmethod_cache);
free_simdhash (&mm->gsignature_cache);
free_hash (&mm->szarray_cache);
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19 changes: 11 additions & 8 deletions src/mono/mono/metadata/metadata.c
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Expand Up @@ -38,6 +38,7 @@
#include <mono/utils/atomic.h>
#include <mono/utils/unlocked.h>
#include <mono/utils/mono-logger-internals.h>
#include "../native/containers/dn-simdhash-utils.h"

/* Auxiliary structure used for caching inflated signatures */
typedef struct {
Expand Down Expand Up @@ -1874,18 +1875,21 @@ mono_type_equal (gconstpointer ka, gconstpointer kb)
guint
mono_metadata_generic_inst_hash (gconstpointer data)
{
// Custom MurmurHash3 for generic instances to produce a high quality hash
const MonoGenericInst *ginst = (const MonoGenericInst *) data;
guint hash = 0;
g_assert (ginst);
g_assert (ginst->type_argv);

uint32_t h1 = ginst->type_argc;

for (guint i = 0; i < ginst->type_argc; ++i) {
hash *= 13;
g_assert (ginst->type_argv [i]);
hash += mono_metadata_type_hash (ginst->type_argv [i]);
MURMUR3_HASH_BLOCK ((uint32_t) mono_metadata_type_hash (ginst->type_argv [i]));
}

return hash ^ (ginst->is_open << 8);
h1 ^= ginst->is_open;

return (guint)murmur3_fmix32 (h1);
}

static gboolean
Expand Down Expand Up @@ -3494,10 +3498,9 @@ mono_metadata_get_canonical_generic_inst (MonoGenericInst *candidate)
mono_loader_lock ();

if (!mm->ginst_cache)
mm->ginst_cache = dn_simdhash_ght_new_full (mono_metadata_generic_inst_hash, mono_metadata_generic_inst_equal, NULL, (GDestroyNotify)free_generic_inst, 0, NULL);
mm->ginst_cache = g_hash_table_new_full (mono_metadata_generic_inst_hash, mono_metadata_generic_inst_equal, NULL, (GDestroyNotify)free_generic_inst);

MonoGenericInst *ginst = NULL;
dn_simdhash_ght_try_get_value (mm->ginst_cache, candidate, (void **)&ginst);
MonoGenericInst *ginst = g_hash_table_lookup (mm->ginst_cache, candidate);
if (!ginst) {
int size = MONO_SIZEOF_GENERIC_INST + type_argc * sizeof (MonoType *);
ginst = (MonoGenericInst *)mono_mem_manager_alloc0 (mm, size);
Expand All @@ -3511,7 +3514,7 @@ mono_metadata_get_canonical_generic_inst (MonoGenericInst *candidate)
for (int i = 0; i < type_argc; ++i)
ginst->type_argv [i] = mono_metadata_type_dup (NULL, candidate->type_argv [i]);

dn_simdhash_ght_insert (mm->ginst_cache, ginst, ginst);
g_hash_table_insert (mm->ginst_cache, ginst, ginst);
}

mono_loader_unlock ();
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