From 7e833f301eeca5114be3315ec4f4385cf34977af Mon Sep 17 00:00:00 2001 From: =?utf8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Wed, 25 Sep 2019 12:06:05 +0200 Subject: [PATCH] basic: massively reduce the size of arphdr lookup functions Our biggest object in libsystemd was a table full of zeros, for the arphdr names. Let's use a switch (which gcc nicely optimizes for us), instead a table with a gap between 826 and 65534: $ ls -l build{,2}/src/basic/a6ba3eb@@basic@sta/arphrd-list.c.o -rw-rw-r--. 1 zbyszek zbyszek 540232 Sep 22 00:29 build/src/basic/a6ba3eb\@\@basic\@sta/arphrd-list.c.o -rw-rw-r--. 1 zbyszek zbyszek 20512 Sep 25 11:56 build2/src/basic/a6ba3eb\@\@basic\@sta/arphrd-list.c.o $ ls -l build{,2}/src/shared/libsystemd-shared-243.so -rwxrwxr-x. 1 zbyszek zbyszek 6774368 Sep 22 00:29 build/src/shared/libsystemd-shared-243.so -rwxrwxr-x. 1 zbyszek zbyszek 6254808 Sep 25 12:16 build2/src/shared/libsystemd-shared-243.so No functional change. --- src/basic/arphrd-list.c | 15 --------------- src/basic/arphrd-list.h | 2 -- src/basic/arphrd-to-name.awk | 11 +++++++---- src/test/test-arphrd-list.c | 22 +++++++++------------- 4 files changed, 16 insertions(+), 34 deletions(-) diff --git a/src/basic/arphrd-list.c b/src/basic/arphrd-list.c index b9a9cb7..7e5570a 100644 --- a/src/basic/arphrd-list.c +++ b/src/basic/arphrd-list.c @@ -12,17 +12,6 @@ static const struct arphrd_name* lookup_arphrd(register const char *str, registe #include "arphrd-from-name.h" #include "arphrd-to-name.h" -const char *arphrd_to_name(int id) { - - if (id <= 0) - return NULL; - - if ((size_t) id >= ELEMENTSOF(arphrd_names)) - return NULL; - - return arphrd_names[id]; -} - int arphrd_from_name(const char *name) { const struct arphrd_name *sc; @@ -34,7 +23,3 @@ int arphrd_from_name(const char *name) { return sc->id; } - -int arphrd_max(void) { - return ELEMENTSOF(arphrd_names); -} diff --git a/src/basic/arphrd-list.h b/src/basic/arphrd-list.h index 5dcfe5e..aae56bc 100644 --- a/src/basic/arphrd-list.h +++ b/src/basic/arphrd-list.h @@ -3,5 +3,3 @@ const char *arphrd_to_name(int id); int arphrd_from_name(const char *name); - -int arphrd_max(void); diff --git a/src/basic/arphrd-to-name.awk b/src/basic/arphrd-to-name.awk index 5a35673..4600dbf 100644 --- a/src/basic/arphrd-to-name.awk +++ b/src/basic/arphrd-to-name.awk @@ -1,9 +1,12 @@ BEGIN{ - print "static const char* const arphrd_names[] = { " + print "const char *arphrd_to_name(int id) {" + print " switch(id) {" } -!/CISCO/ { - printf " [ARPHRD_%s] = \"%s\",\n", $1, $1 +!/CISCO|NETROM/ { + printf " case ARPHRD_%s: return \"%s\";\n", $1, $1 } END{ - print "};" + print " default: return NULL;" + print " }" + print "}" } diff --git a/src/test/test-arphrd-list.c b/src/test/test-arphrd-list.c index e5c50f3..3010ca6 100644 --- a/src/test/test-arphrd-list.c +++ b/src/test/test-arphrd-list.c @@ -1,31 +1,27 @@ /* SPDX-License-Identifier: LGPL-2.1+ */ #include -#include -#include "macro.h" #include "string-util.h" #include "tests.h" -_unused_ \ -static const struct arphrd_name* lookup_arphrd(register const char *str, register GPERF_LEN_TYPE len); - -#include "arphrd-from-name.h" #include "arphrd-list.h" -#include "arphrd-to-name.h" int main(int argc, const char *argv[]) { test_setup_logging(LOG_INFO); - for (unsigned i = 1; i < ELEMENTSOF(arphrd_names); i++) - if (arphrd_names[i]) { - log_info("%i: %s", i, arphrd_to_name(i)); + for (int i = 0; i <= ARPHRD_VOID + 1; i++) { + const char *name; + + name = arphrd_to_name(i); + if (name) { + log_info("%i: %s", i, name); - assert_se(streq(arphrd_to_name(i), arphrd_names[i])); - assert_se(arphrd_from_name(arphrd_names[i]) == (int) i); + assert_se(arphrd_from_name(name) == i); } + } - assert_se(arphrd_to_name(arphrd_max()) == NULL); + assert_se(arphrd_to_name(ARPHRD_VOID + 1) == NULL); assert_se(arphrd_to_name(0) == NULL); assert_se(arphrd_from_name("huddlduddl") == -EINVAL); assert_se(arphrd_from_name("") == -EINVAL); -- 2.7.4