From 9295e58ae706a3734f6fa80704c41502ba73131e Mon Sep 17 00:00:00 2001
From: penguin_wwy <940375606@qq.com>
Date: Thu, 21 Nov 2024 00:34:34 +0800
Subject: [PATCH] perf(python): Pre-allocate size for the dictionary (#1949)

## What does this PR do?

Pre-allocate memory for the dictionary based on the data size to avoid
resizing and improve deserialization performance.

## Related issues

## Does this PR introduce any user-facing change?

- [ ] Does this PR introduce any public API change?
- [ ] Does this PR introduce any binary protocol compatibility change?

## Benchmark
```
# python format
fury_large_dict: Mean +- std dev: [dict_base] 548 us +- 33 us -> [dict_resize] 531 us +- 33 us: 1.03x faster

# xlang format
fury_large_dict: Mean +- std dev: [dict_xlang_base] 550 us +- 39 us -> [dict_xlang_resize] 527 us +- 35 us: 1.05x faster
```
---
 integration_tests/cpython_benchmark/fury_benchmark.py | 4 ++++
 python/pyfury/_serialization.pyx                      | 7 ++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/integration_tests/cpython_benchmark/fury_benchmark.py b/integration_tests/cpython_benchmark/fury_benchmark.py
index 8b493aec94..01be1d49a4 100644
--- a/integration_tests/cpython_benchmark/fury_benchmark.py
+++ b/integration_tests/cpython_benchmark/fury_benchmark.py
@@ -64,6 +64,7 @@
     "view_count": 7,
     "zip": "",
 }
+LARGE_DICT = {str(i): i for i in range(2**10 + 1)}
 
 TUPLE = (
     [
@@ -177,6 +178,9 @@ def micro_benchmark():
     runner.parse_args()
     language = pyfury.Language.XLANG if args.xlang else pyfury.Language.PYTHON
     runner.bench_func("fury_dict", fury_object, language, not args.no_ref, DICT)
+    runner.bench_func(
+        "fury_large_dict", fury_object, language, not args.no_ref, LARGE_DICT
+    )
     runner.bench_func(
         "fury_dict_group", fury_object, language, not args.no_ref, DICT_GROUP
     )
diff --git a/python/pyfury/_serialization.pyx b/python/pyfury/_serialization.pyx
index 0175f6151a..ce1443c65f 100644
--- a/python/pyfury/_serialization.pyx
+++ b/python/pyfury/_serialization.pyx
@@ -76,6 +76,7 @@ cdef extern from *:
     """
     object int2obj(int64_t obj_addr)
     int64_t obj2int(object obj_ref)
+    dict _PyDict_NewPresized(Py_ssize_t minused)
 
 
 cdef int8_t NULL_FLAG = -3
@@ -2081,9 +2082,9 @@ cdef class MapSerializer(Serializer):
     cpdef inline read(self, Buffer buffer):
         cdef MapRefResolver ref_resolver = self.ref_resolver
         cdef ClassResolver class_resolver = self.class_resolver
-        cdef dict map_ = {}
-        ref_resolver.reference(map_)
         cdef int32_t len_ = buffer.read_varint32()
+        cdef dict map_ = _PyDict_NewPresized(len_)
+        ref_resolver.reference(map_)
         cdef int32_t ref_id
         cdef ClassInfo key_classinfo
         cdef ClassInfo value_classinfo
@@ -2131,7 +2132,7 @@ cdef class MapSerializer(Serializer):
 
     cpdef inline xread(self, Buffer buffer):
         cdef int32_t len_ = buffer.read_varint32()
-        cdef dict map_ = {}
+        cdef dict map_ = _PyDict_NewPresized(len_)
         self.fury.ref_resolver.reference(map_)
         for i in range(len_):
             k = self.fury.xdeserialize_ref(