From 514ef0f93b76cbe0ba6b4de07a7b21fd0c2b7bae Mon Sep 17 00:00:00 2001 From: q66 Date: Thu, 6 Jun 2024 13:45:48 +0200 Subject: [PATCH] strbuf: use GREEDY_REALLOC to grow the buffer This allows us to reserve a bunch of capacity ahead of time, improving the performance of hwdb significantly thanks to not having to reallocate so many times. Before: ``` $ sudo time valgrind --leak-check=full ./systemd-hwdb update ==113297== Memcheck, a memory error detector ==113297== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al. ==113297== Using Valgrind-3.23.0 and LibVEX; rerun with -h for copyright info ==113297== Command: ./systemd-hwdb update ==113297== ==113297== ==113297== HEAP SUMMARY: ==113297== in use at exit: 0 bytes in 0 blocks ==113297== total heap usage: 1,412,640 allocs, 1,412,640 frees, 117,920,009,195 bytes allocated ==113297== ==113297== All heap blocks were freed -- no leaks are possible ==113297== ==113297== For lists of detected and suppressed errors, rerun with: -s ==113297== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0) 132.44user 21.15system 2:35.61elapsed 98%CPU (0avgtext+0avgdata 228560maxresident)k 0inputs+25296outputs (0major+6886930minor)pagefaults 0swaps ``` After: ``` $ sudo time valgrind --leak-check=full ./systemd-hwdb update ==112572== Memcheck, a memory error detector ==112572== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al. ==112572== Using Valgrind-3.23.0 and LibVEX; rerun with -h for copyright info ==112572== Command: ./systemd-hwdb update ==112572== ==112572== ==112572== HEAP SUMMARY: ==112572== in use at exit: 0 bytes in 0 blocks ==112572== total heap usage: 1,320,113 allocs, 1,320,113 frees, 70,614,501 bytes allocated ==112572== ==112572== All heap blocks were freed -- no leaks are possible ==112572== ==112572== For lists of detected and suppressed errors, rerun with: -s ==112572== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0) 21.94user 0.19system 0:22.23elapsed 99%CPU (0avgtext+0avgdata 229876maxresident)k 0inputs+25264outputs (0major+57275minor)pagefaults 0swaps ``` Co-authored-by: Yu Watanabe (cherry picked from commit 621b10fe2c3203c537996e84c7c89b0ff994ad93) --- src/basic/strbuf.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/src/basic/strbuf.c b/src/basic/strbuf.c index 0617acc8d2..6d43955bb1 100644 --- a/src/basic/strbuf.c +++ b/src/basic/strbuf.c @@ -107,7 +107,6 @@ static void bubbleinsert(struct strbuf_node *node, /* add string, return the index/offset into the buffer */ ssize_t strbuf_add_string(struct strbuf *str, const char *s, size_t len) { uint8_t c; - char *buf_new; struct strbuf_child_entry *child; struct strbuf_node *node; ssize_t off; @@ -147,10 +146,8 @@ ssize_t strbuf_add_string(struct strbuf *str, const char *s, size_t len) { } /* add new string */ - buf_new = realloc(str->buf, str->len + len+1); - if (!buf_new) + if (!GREEDY_REALLOC(str->buf, str->len + len + 1)) return -ENOMEM; - str->buf = buf_new; off = str->len; memcpy(str->buf + off, s, len); str->len += len;