comparison mercurial/bdiff_module.c @ 31467:08ecec297521

bdiff: use Python memory allocator in fixws Python has its own memory allocation APIs. For allocations <= 512 bytes, it allocates memory from arenas. This means that average small allocations don't call the system allocator, which makes them faster. Also, arena allocations cut down on memory fragmentation, which can matter for performance in long-running processes. Another advantage of using the Python memory allocator is that allocations are tracked by Python. This is a bigger deal in Python 3, as modern versions of Python have some decent built-in tools for examining memory usage, leaks, etc. This patch converts a trivial malloc() + free() in the bdiff code to use the Python allocator APIs. Since the object being operated on is a line, chances are it will use an arena. So, this could have a net positive impact on performance (although I didn't measure it).
author Gregory Szorc <gregory.szorc@gmail.com>
date Thu, 09 Mar 2017 11:54:25 -0800
parents 7c0c722d568d
children 4195b84940e9
comparison
equal deleted inserted replaced
31466:b6bbfbaa205a 31467:08ecec297521
156 if (!PyArg_ParseTuple(args, "Sb:fixws", &s, &allws)) 156 if (!PyArg_ParseTuple(args, "Sb:fixws", &s, &allws))
157 return NULL; 157 return NULL;
158 r = PyBytes_AsString(s); 158 r = PyBytes_AsString(s);
159 rlen = PyBytes_Size(s); 159 rlen = PyBytes_Size(s);
160 160
161 w = (char *)malloc(rlen ? rlen : 1); 161 w = (char *)PyMem_Malloc(rlen ? rlen : 1);
162 if (!w) 162 if (!w)
163 goto nomem; 163 goto nomem;
164 164
165 for (i = 0; i != rlen; i++) { 165 for (i = 0; i != rlen; i++) {
166 c = r[i]; 166 c = r[i];
176 } 176 }
177 177
178 result = PyBytes_FromStringAndSize(w, wlen); 178 result = PyBytes_FromStringAndSize(w, wlen);
179 179
180 nomem: 180 nomem:
181 free(w); 181 PyMem_Free(w);
182 return result ? result : PyErr_NoMemory(); 182 return result ? result : PyErr_NoMemory();
183 } 183 }
184 184
185 185
186 static char mdiff_doc[] = "Efficient binary diff."; 186 static char mdiff_doc[] = "Efficient binary diff.";