Closed Bug 787568 Opened 8 years ago Closed 8 years ago

Upgrade clang to r161152

Categories

(Release Engineering :: General, defect)

x86_64
Linux
defect
Not set
normal

Tracking

(Not tracked)

RESOLVED FIXED

People

(Reporter: espindola, Assigned: espindola)

References

Details

Attachments

(2 files)

Testing bug 784691 found a performance regression and lots of hard to reproduce issues. As part of trying to figure it out I tested r161152 on try with the new diff-talos.py and found that r161152 was not the one responsible for the regression.

Since the build is tested, deployed and doesn't cause any regressions, it is probably a good idea to enable it as a stepping stone.
Attachment #657454 - Flags: review?(rail)
Attachment #657454 - Flags: review?(rail) → review+
Attachment #657455 - Flags: review?(rail) → review+
I forgot to clobber the build, so to test the results at the time of the switch I did a dummy try push and one reverting the change. The results found by

diff-talos.py d1e8ba348798 19df46b223c2

are

--------------------------------------------------------------
dromaeo_css
MacOSX 10.8                       | (5387.485,     20.6175526751)  -> (5428.5875,    13.8504870083)  1.0076x better

dromaeo_dom
MacOSX 10.7                       | (281.467833333, 1.47639194691) -> (278.4475,     1.04198602984)  1.0108x worse

kraken
MacOSX 10.8                       | (3334.36666667, 6.37096002557) -> (3315.59166667, 4.94021473626) 1.0057x better

-------------------------------------------------------

Which is not amusing given that the try runs before the switch had no significant regressions :-(
Given that the regression (and the speedup) only show up in one version of OS X and we run the same binary on 3 of them, it is very likely this is just some form of bias on our testing, but I don't have time to check it right now as I am going on vacations.

CCing ehsan to decide if this should be reverted for now.
(In reply to comment #3)
> CCing ehsan to decide if this should be reverted for now.

Hmm, this is a tough call.  Do these clang versions provide us with other benefits?
> Hmm, this is a tough call.  Do these clang versions provide us with other
> benefits?

Mostly being a stepping stone for upgrading to r162360 in bug 784691 and that revision has a fix for http://llvm.org/pr13662.
Blocks: 793643
Product: mozilla.org → Release Engineering
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