search

llvm / llvm-project

The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
http://llvm.org
Other
27.92k stars 11.52k forks source link

Regression(likely r268806): Building llvm takes 20% longer than it used to #28074

Open nico opened 8 years ago

nico commented 8 years ago
Bugzilla Link 27700
Version trunk
OS Linux
CC @compnerd,@bogner,@rnk

Extended Description

We have a bunch of bots that basically do:

  1. svn up llvm, run cmake, run ninja to build all of llvm
  2. build Chromium with that just-built clang

The time of the first step increased by about 20% on all our bots. The regression range is r268806:268820 (both ends inclusive). Maybe r268806 makes things slow for some reason?

nico commented 8 years ago

I looked at one other bot (maybe https://build.chromium.org/p/chromium.fyi/stats/ClangToTWin(dll) ?) and combined the regression ranges from that bot with the linux one. The upper bound is from the linux bot, the lower one from the other bot.

rnk commented 8 years ago

Are you sure the Window is right? Based on the linked bot, these are the two builds bracketing the regression: https://build.chromium.org/p/chromium.fyi/builders/ClangToTLinux/builds/5130 https://build.chromium.org/p/chromium.fyi/builders/ClangToTLinux/builds/5129

The clang window for that is (r268787, r268820].

r268806 doesn't seem like a plausible culprit given that we don't run tests.

I don't see a good culprit on the LLVM side (git log 3a963d121a2e690698987c175ca9760007e87935...9c0ef542c413c898248f2d682851c6b56314673a).

nico commented 8 years ago

screenshot

nico commented 8 years ago

We don't run LLVM tests on these bots.

Here's a graph: https://build.chromium.org/p/chromium.fyi/stats/ClangToTLinux (scroll all the way to the bottom to "runhooks")