From 8eb92e605200b1fe8d570ad309e28245c3f1af0a Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Fri, 21 Dec 2012 12:21:59 +0400 Subject: [PATCH] Optimize cstr_reset() to only reset string to empty, not call free() and later malloc() A CString could be reset to empty just setting its .size to 0. If memory was already allocated, that would be remembered in .data_allocated and .size_allocated and on consequent string manipulations that memory will be used without immediate need to call malloc(). For $ ./tcc -B. -bench -DONE_SOURCE -DCONFIG_MULTIARCHDIR=\"i386-linux-gnu\" -c tcc.c after the patch malloc/free are called less often: (tcc is run in loop; perf record -a sleep 10 && perf report) before: # Overhead Command Shared Object Symbol # ........ ........... .................. .......................................... # 13.89% tcc tcc [.] next_nomacro1 4.73% tcc libc-2.13.so [.] _int_malloc 4.39% tcc tcc [.] next 2.94% tcc tcc [.] tok_str_add2 2.78% tcc tcc [.] macro_subst_tok 2.75% tcc libc-2.13.so [.] free 2.74% tcc tcc [.] macro_subst 2.63% tcc libc-2.13.so [.] _int_free 2.28% tcc tcc [.] vswap 2.24% tcc tcc [.] next_nomacro_spc 2.06% tcc libc-2.13.so [.] realloc 2.00% tcc libc-2.13.so [.] malloc 1.99% tcc tcc [.] unary 1.85% tcc libc-2.13.so [.] __i686.get_pc_thunk.bx 1.76% kworker/0:1 [kernel.kallsyms] [k] delay_tsc 1.70% tcc tcc [.] next_nomacro 1.62% tcc tcc [.] preprocess 1.41% tcc libc-2.13.so [.] __memcmp_ssse3 1.38% tcc [kernel.kallsyms] [k] memset 1.10% tcc tcc [.] g 1.06% tcc tcc [.] parse_btype 1.05% tcc tcc [.] sym_push2 1.04% tcc libc-2.13.so [.] _int_realloc 1.00% tcc libc-2.13.so [.] malloc_consolidate after: # Overhead Command Shared Object Symbol # ........ ........... .................. .............................................. # 15.26% tcc tcc [.] next_nomacro1 5.07% tcc libc-2.13.so [.] _int_malloc 4.62% tcc tcc [.] next 3.22% tcc tcc [.] tok_str_add2 3.03% tcc tcc [.] macro_subst_tok 3.02% tcc tcc [.] macro_subst 2.59% tcc tcc [.] next_nomacro_spc 2.44% tcc tcc [.] vswap 2.39% tcc libc-2.13.so [.] _int_free 2.28% tcc libc-2.13.so [.] free 2.22% tcc tcc [.] unary 2.07% tcc libc-2.13.so [.] realloc 1.97% tcc libc-2.13.so [.] malloc 1.70% tcc tcc [.] preprocess 1.69% tcc libc-2.13.so [.] __i686.get_pc_thunk.bx 1.68% tcc tcc [.] next_nomacro 1.59% tcc [kernel.kallsyms] [k] memset 1.55% tcc libc-2.13.so [.] __memcmp_ssse3 1.22% tcc tcc [.] parse_comment 1.11% tcc tcc [.] g 1.11% tcc tcc [.] sym_push2 1.10% tcc tcc [.] parse_btype 1.10% tcc libc-2.13.so [.] _int_realloc 1.06% tcc tcc [.] vsetc 0.98% tcc libc-2.13.so [.] malloc_consolidate and this gains small speedup for tcc: # best of 5 runs before: 8268 idents, 47191 lines, 1526670 bytes, 0.153 s, 307997 lines/s, 10.0 MB/s after: 8268 idents, 47203 lines, 1526763 bytes, 0.148 s, 319217 lines/s, 10.3 MB/s --- tcc.h | 2 +- tccpp.c | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/tcc.h b/tcc.h index fe870d84..48a42f26 100644 --- a/tcc.h +++ b/tcc.h @@ -1008,7 +1008,7 @@ PUB_FUNC void cstr_cat(CString *cstr, const char *str); PUB_FUNC void cstr_wccat(CString *cstr, int ch); PUB_FUNC void cstr_new(CString *cstr); PUB_FUNC void cstr_free(CString *cstr); -#define cstr_reset(cstr) cstr_free(cstr) +PUB_FUNC void cstr_reset(CString *cstr); ST_FUNC Section *new_section(TCCState *s1, const char *name, int sh_type, int sh_flags); ST_FUNC void section_realloc(Section *sec, unsigned long new_size); diff --git a/tccpp.c b/tccpp.c index b80c986c..4b7b4fa8 100644 --- a/tccpp.c +++ b/tccpp.c @@ -163,6 +163,12 @@ PUB_FUNC void cstr_free(CString *cstr) cstr_new(cstr); } +/* reset string to empty */ +PUB_FUNC void cstr_reset(CString *cstr) +{ + cstr->size = 0; +} + /* XXX: unicode ? */ static void add_char(CString *cstr, int c) { -- 2.11.4.GIT