From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753503Ab3JAP3R (ORCPT ); Tue, 1 Oct 2013 11:29:17 -0400 Received: from mail-ea0-f172.google.com ([209.85.215.172]:34470 "EHLO mail-ea0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751267Ab3JAP3I (ORCPT ); Tue, 1 Oct 2013 11:29:08 -0400 Date: Tue, 1 Oct 2013 17:29:04 +0200 From: Ingo Molnar To: Arnaldo Carvalho de Melo Cc: Linus Torvalds , David Ahern , Linux Kernel Mailing List , Peter Zijlstra , Thomas Gleixner , Andrew Morton , Jiri Olsa , Namhyung Kim Subject: [PATCH] perf tools: Speed up the final link Message-ID: <20131001152904.GA1262@gmail.com> References: <20130912203116.GD32644@gmail.com> <20130912204313.GA3259@gmail.com> <20130915091029.GA21465@gmail.com> <20130930164210.GA22342@gmail.com> <20130930171220.GC10293@ghostprotocols.net> <20130930175342.GI10293@ghostprotocols.net> <20130930190434.GA3427@gmail.com> <20131001113456.GA31331@gmail.com> <20131001152757.GB8970@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131001152757.GB8970@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (Sent with proper subject line.) =================> libtraceevent.a and liblk.a rules have always-missed dependencies, which causes python.so to be relinked at every build attempt - even if none of the affected code changes. This slows down re-builds unnecessarily, by adding more than a second to the build time: comet:~/tip/tools/perf> time make ... SUBDIR /fast/mingo/tip/tools/lib/lk/ make[1]: `liblk.a' is up to date. SUBDIR /fast/mingo/tip/tools/lib/traceevent/ LINK perf GEN python/perf.so real 0m1.701s user 0m1.338s sys 0m0.301s Add the (trivial) dependencies to not force a re-link. This speeds up an empty re-build enormously: comet:~/tip/tools/perf> time make ... real 0m0.207s user 0m0.134s sys 0m0.028s [ This adds some coupling between the build dependencies of libtraceevent and liblk - but until those stay relatively simple this should not be an issue. ] Signed-off-by: Ingo Molnar --- tools/perf/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) Index: tip/tools/perf/Makefile =================================================================== --- tip.orig/tools/perf/Makefile +++ tip/tools/perf/Makefile @@ -669,15 +669,19 @@ $(LIB_FILE): $(LIB_OBJS) $(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIB_OBJS) # libtraceevent.a -$(LIBTRACEEVENT): +TE_SOURCES = $(wildcard $(TRACE_EVENT_DIR)*.[ch]) + +$(LIBTRACEEVENT): $(TE_SOURCES) $(QUIET_SUBDIR0)$(TRACE_EVENT_DIR) $(QUIET_SUBDIR1) O=$(OUTPUT) libtraceevent.a $(LIBTRACEEVENT)-clean: $(QUIET_SUBDIR0)$(TRACE_EVENT_DIR) $(QUIET_SUBDIR1) O=$(OUTPUT) clean +LIBLK_SOURCES = $(wildcard $(LK_PATH)*.[ch]) + # if subdir is set, we've been called from above so target has been built # already -$(LIBLK): +$(LIBLK): $(LIBLK_SOURCES) ifeq ($(subdir),) $(QUIET_SUBDIR0)$(LK_DIR) $(QUIET_SUBDIR1) O=$(OUTPUT) liblk.a endif @@ -824,7 +828,7 @@ else GIT-HEAD-PHONY = endif -.PHONY: all install clean strip $(LIBTRACEEVENT) $(LIBLK) +.PHONY: all install clean strip .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell .PHONY: $(GIT-HEAD-PHONY) TAGS tags cscope .FORCE-PERF-CFLAGS