Simon, you are on windows, correct? If so the result you posted is using the "x86_64-linux-deb9" environment as a baseline when it should be using "x86_64" which is much closer to the result you're getting.
WSL actually. (Windows Subsystem for Linux.)
Simon
From: David Eichmann
So it's just an implementation detail whether the numbers you save are gotten from one run, or another identical one.
For the most part yes, but since we usually rebase and batch commit with marge bot, we are really creating a new commit. So it makes some sense to rerun CI.
The CI log tells you the comparison between the preceding commit and this one
I'd love for this to be the behavior too. The problem is, most of the time we don't have the metrics for the parent commit, and generating them is expensive. We could automatically checkout / build the previous commit and run perf tests, but this doesn't seem like good design. That's why we've resorted to searching for "most recent" local or CI metrics to establish an approximate baseline. Requiring the developers to always run perf tests locally on the previous commit will be extremely annoying. Another option is to just disable perf tests by default. It's not satisfying but it's hard to think of a better solution. I think the current implementation is still more convenient than before, where baselines were just hard coded into test files. If you wanted to investigate a particular commit, you had to manually establish a baseline. Perhaps the problem with this new system is that it's a bit too "magical" and it's unclear how to interpret results. Perhaps this can be remedied with better output form the test runner.
Would it be possible to output a table (in the log) like we get from nofib-analyse
Absolutely. This should be fairly easy to implement. I've created #18417.
- David E
On 6/29/20 3:08 PM, Simon Peyton Jones wrote:
Re the doubling of bytes-allocated on T9803, that's a good point. Due to the recent change in RSA keys, CI is recently failing to upload metrics (e.g. [1])! I'll fix that then see if I can track down where / if the metric has really regressed in master.
Thanks
Yes we run CI on MRs, but once merged into master CI is run again. It's only those metrics from CI on master (post merge) that are ultimately uploaded / used as a baseline.
OK. But they are guaranteed to be 100.0% identical to the ones discovered by CI, aren't they? So it's just an implementation detail whether the numbers you save are gotten from one run, or another identical one.
I'm still lost about when I can rely on the perf output of CI and when I can't. I'm really hoping for a simple answer like:
* The CI log tells you the comparison between the preceding commit and this one
No ifs, no buts. Simple!
Incidentally, would it be possible to output a table (in the log) like we get from nofib-analyse. It looks like this
Program Size Allocs Runtime Elapsed TotalMem
--------------------------------------------------------------------------------
boyer -0.3% +5.4% +0.7% +1.0% 0.0%
cichelli -0.3% +5.9% -9.9% -9.5% 0.0%
compress2 -0.4% +9.6% +7.2% +6.4% 0.0%
constraints -0.3% +0.2% -3.0% -3.4% 0.0%
cryptarithm2 -0.3% -3.9% -2.2% -2.4% 0.0%
gamteb -0.4% +2.5% +2.8% +2.8% 0.0%
life -0.3% -2.2% -4.7% -4.9% 0.0%
lift -0.3% -0.3% -0.8% -0.5% 0.0%
linear -0.3% -0.1% -4.1% -4.5% 0.0%
mate -0.2% +1.4% -2.2% -1.9% -14.3%
parser -0.3% -2.1% -5.4% -4.6% 0.0%
puzzle -0.3% +2.1% -6.6% -6.3% 0.0%
simple -0.4% +2.8% -3.4% -3.3% -2.2%
veritas -0.1% +0.7% -0.6% -1.1% 0.0%
wheel-sieve2 -0.3% -19.2% -24.9% -24.5% -42.9%
--------------------------------------------------------------------------------
Min -0.4% -19.2% -24.9% -24.5% -42.9%
Max +0.1% +9.6% +7.2% +6.4% +33.3%
Geometric Mean -0.3% -0.0% -3.0% -2.9% -0.3%
Instantly comprehensible, one line per benchmark. I find I spent quite a lot of time search manually in the log and manually building a table (or excerpts thereof) looking like this.
I don't have an opinion about the columns, just wanting a table with one line per benchmark, and a number of columns.
Thanks
Simon
From: David Eichmann
I thought that wasn't possible. Isn't that what CI is *for*?
Yes we run CI on MRs, but once merged into master CI is run again. It's only those metrics from CI on master (post merge) that are ultimately uploaded / used as a baseline. Re the doubling of bytes-allocated on T9803, that's a good point. Due to the recent change in RSA keys, CI is recently failing to upload metrics (e.g. [1])! I'll fix that then see if I can track down where / if the metric has really regressed in master. [1] "fatal: Could not read from remote repository." https://gitlab.haskell.org/ghc/ghc/-/jobs/378487https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.haskell.org%2Fghc%2Fghc%2F-%2Fjobs%2F378487&data=02%7C01%7Csimonpj%40microsoft.com%7Cc4f75c38623e40b4983608d81e9c118a%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637293004078959683&sdata=1obE6D2oHoZxYizjzOAsxqOcW%2B3PcY6kqfckNgKFFQg%3D&reserved=0 -- David Eichmann, Haskell Consultant Well-Typed LLP, http://www.well-typed.comhttps://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.well-typed.com%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cc4f75c38623e40b4983608d81e9c118a%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637293004078969677&sdata=lk2tF4MQQwKPoMO2ABXuWXI871hTlPNXb0O5YICa5Bg%3D&reserved=0 Registered in England & Wales, OC335890 118 Wymering Mansions, Wymering Road, London W9 2NF, England -- David Eichmann, Haskell Consultant Well-Typed LLP, http://www.well-typed.comhttps://nam06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.well-typed.com%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cc4f75c38623e40b4983608d81e9c118a%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637293004078969677&sdata=lk2tF4MQQwKPoMO2ABXuWXI871hTlPNXb0O5YICa5Bg%3D&reserved=0 Registered in England & Wales, OC335890 118 Wymering Mansions, Wymering Road, London W9 2NF, England