Hi, When php script includes a script, php engine compiles the included file. When opcode caching extensions e.g apc are used, re-compilation is avoided by apc. But there is a performance problem here. Since php code uses zend_stream_open to open the included file, open/close system call is still there. When used with APC, open/close doesn't do any good for file-system based files. It only provides the realpath of the opened file. In php 5.3, zend_resolve_path already provides the realpath of the file being opened so we can avoid an open/close calls for file to be included if file is an absolute path.
Current php 5.3 implementation for include_once/require_once (pseudo code) a) call zend_resolve_path. It will provide the realpath. Symlinks are taken care of by zend_resolve_path. b) Check if file is already included. If yes, do nothing else go to step (c) c) Call zend_stream_open and get the included_file realpath. d) Invoke zend_compile_file and do the rest. Now zend_stream_open invokes the open/close calls to the including files which is redundant when caches are used. Here is the suggested performance fix : a) Same as previous b) Same as previous c) If resolved_path is an absolute path then do step c.1 else do c.2 c.1) Prepare a file_handle and directly invoke zend_compile_file c.2 Call zend_stream_open and get the included_file realpath. b) Same as previous --------------------------------------------------- Few notes : * Performance improvements using this patch = ~1.5% in an e-commerce workload. * Testing : I ran the php 5.3 test suite and didn't find any regression. * If files which are included are not absolute paths then they will follow the same zend_stream_path route. * Tested with symlinks and found the behaviour is expected (no change). I have attached the patch for review comments. Regards, Basant. Note: I previously did this work for php 5.2 but bug remains still open. 5.3 implementation is relatively straight forward. Here is the reference to 5.2 bug : http://bugs.php.net/bug.php?id=47660&thanks=2
Index: Zend/zend_vm_def.h =================================================================== --- Zend/zend_vm_def.h (revision 290447) +++ Zend/zend_vm_def.h (working copy) @@ -3213,16 +3213,38 @@ case ZEND_REQUIRE_ONCE: { zend_file_handle file_handle; char *resolved_path; + int is_resolved_abs_path = 0; resolved_path = zend_resolve_path(Z_STRVAL_P(inc_filename), Z_STRLEN_P(inc_filename) TSRMLS_CC); if (resolved_path) { - failure_retval = zend_hash_exists(&EG(included_files), resolved_path, strlen(resolved_path)+1); + int len = strlen(resolved_path); + failure_retval = zend_hash_exists(&EG(included_files), resolved_path, len+1); + if (IS_ABSOLUTE_PATH(resolved_path, len + 1)) + is_resolved_abs_path = 1; } else { resolved_path = Z_STRVAL_P(inc_filename); } if (failure_retval) { /* do nothing, file already included */ + } else if (is_resolved_abs_path) { + /* file is a absolute file name and resolved_path contains the realpath */ + int type = (Z_LVAL(opline->op2.u.constant) == ZEND_INCLUDE_ONCE ? + ZEND_INCLUDE : ZEND_REQUIRE); + file_handle.filename = resolved_path; + file_handle.free_filename = 0; + file_handle.type = ZEND_HANDLE_FILENAME; + file_handle.opened_path = NULL; + file_handle.handle.fp = NULL; + + new_op_array = zend_compile_file(&file_handle, type TSRMLS_CC); + if (!file_handle.opened_path) { + file_handle.opened_path = estrdup(resolved_path); + } + if (zend_hash_add_empty_element(&EG(included_files), file_handle.opened_path, strlen(file_handle.opened_path)+1)!=SUCCESS) { + failure_retval=1; + } + zend_destroy_file_handle(&file_handle TSRMLS_CC); } else if (SUCCESS == zend_stream_open(resolved_path, &file_handle TSRMLS_CC)) { if (!file_handle.opened_path) {
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