From 066dd2632acf11a348ff209b79f42c1a87a71fbb Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Mon, 7 Jul 2014 23:35:11 -0700 Subject: Fix profile feedback with -jN and add profile-fast Profile feedback always failed for me with -jN. The problem was that there was no implicit ordering between the profile generate stage and the profile use stage. So some objects in the later stage would be linked with profile generate objects, and fail due to the missing -lgcov. This adds a new profile target that implicitely enforces the correct ordering by using submakes. Plus a profile-install target to also install. This is also nicer to type that PROFILE=... Plus I always run the performance test suite now for the full profile run. In addition I also added a profile-fast / profile-fast-install target the only runs the performance test suite instead of the whole test suite. This significantly speeds up the profile build, which was totally dominated by test suite run time. However it may have less coverage of course. Signed-off-by: Andi Kleen Signed-off-by: Junio C Hamano --- INSTALL | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'INSTALL') diff --git a/INSTALL b/INSTALL index ba01e7421e..6ec7a24e1a 100644 --- a/INSTALL +++ b/INSTALL @@ -28,7 +28,7 @@ set up install paths (via config.mak.autogen), so you can write instead If you're willing to trade off (much) longer build time for a later faster git you can also do a profile feedback build with - $ make prefix=/usr PROFILE=BUILD all + $ make prefix=/usr profile # make prefix=/usr PROFILE=BUILD install This will run the complete test suite as training workload and then @@ -36,10 +36,20 @@ rebuild git with the generated profile feedback. This results in a git which is a few percent faster on CPU intensive workloads. This may be a good tradeoff for distribution packagers. +Alternatively you can run profile feedback only with the git benchmark +suite. This runs significantly faster than the full test suite, but +has less coverage: + + $ make prefix=/usr profile-fast + # make prefix=/usr PROFILE=BUILD install + Or if you just want to install a profile-optimized version of git into your home directory, you could run: - $ make PROFILE=BUILD install + $ make profile-install + +or + $ make profile-fast-install As a caveat: a profile-optimized build takes a *lot* longer since the git tree must be built twice, and in order for the profiling -- cgit v1.2.1