Bug 19669 - CPU hotspot when working with Expression.Lambda and AOT
Summary: CPU hotspot when working with Expression.Lambda and AOT
Status: RESOLVED NOT_REPRODUCIBLE
Alias: None
Product: iOS
Classification: Xamarin
Component: XI runtime ()
Version: master
Hardware: PC Mac OS
: Normal normal
Target Milestone: Untriaged
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2014-05-11 00:08 UTC by Frank A. Krueger
Modified: 2017-07-25 00:17 UTC (History)
4 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:


Attachments
Image of CPU performance and stacks (1.27 MB, image/png)
2014-05-11 00:08 UTC, Frank A. Krueger
Details


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Status:
RESOLVED NOT_REPRODUCIBLE

Description Frank A. Krueger 2014-05-11 00:08:05 UTC
Created attachment 6777 [details]
Image of CPU performance and stacks

I noticed a hotspot in my CPU performance that revolves around using Linq Expressions and AOT.

Please see the attached image.

The function MocastStorage.AddPodcastEpisodes performs database queries using my sqlite-net library which uses Linq to specify queries.

The AOT calls the method mono_aot_method_hash (aot-compiler.c) which calls mono_type_full_name (debug-helpers.c) which seems to love to play around with copying strings. Is is possible to cache the results of mono_type_full_name or precompile them?
Comment 1 Zoltan Varga 2014-05-11 06:32:20 UTC
That code should only be executed once for each AOT method loaded by the runtime, so it  shouldn't be a hotspot.
Comment 2 Jon Goldberger [MSFT] 2017-07-25 00:17:40 UTC
Thanks so much for taking the time to submit this report! I attempted to reproduce this issue based on the bug description with the latest Xamarin.iOS 10.12.0.14, and I was unable to. If this issue is still occurring for you, please reopen this report and attach a project that reproduces the issue, ideally starting with a new template project and then adding just the code necessary to demonstrate the issue.