Maoni Stephens

loves working on dotnet GC and other perf stuff; avid zoo-goer; wannabe hiphop dancer. old blog

[Maoni Stephens @maoni0]

A Thread - a guideline doc for memory performance analysis for #dotnet #dotnetcore

For the past few weekends I've been working on a (long) document that aims to help you with finding efficient approaches to mem perf problems.

https://t.co/jpYnkxt3Js

[Maoni Stephens @maoni0]

hi folks! it’s been quite a while since I had time to write a blog post. with the upcoming .NET 10 release, I’m finally sharing more details on DATAS and tuning tips you might find useful. check it out here:
https://t.co/aOGw8g5WDd

[Maoni Stephens @maoni0]

@djcp86 @davidfowl @dank_army @dariogriffo @konradkokosa if you hit problems, please feel free to open an issue in the runtime repo on GH (I don't look at X much these days - I was informed of your post by my kind coworkers :-)). I'm still improving it in 10.

[Maoni Stephens @maoni0]

@djcp86 @davidfowl @dank_army @dariogriffo I was going to talk about this at .NET DevDays in Warsaw but I broke my ankle so that didn't happen���

[Maoni Stephens @maoni0]

@djcp86 @davidfowl @dank_army @dariogriffo I mentioned an example in one of my blog posts https://t.co/3ciwRMLqCF.

[Maoni Stephens @maoni0]

@djcp86 @davidfowl @dank_army @dariogriffo sure, here's our official doc page about it: https://t.co/26IG8fCnxK

[Maoni Stephens @maoni0]

@davidfowl @dank_army @dariogriffo I only ported functional changes back to 8, not tuning changes (too much to port). for anyone who wants to try it out, please either try out 9 or get the clrgcexp.dll from 9 and use it with your 8 SDK by replacing the GC with the GCName.

[Maoni Stephens @maoni0]

@dariogriffo @davidfowl is the app using Server GC (if this is an https://t.co/V0yMyWB3rE app it uses Server GC by default)?

[Maoni Stephens @maoni0]

@StudentDanLuis sure thing!

[Maoni Stephens @maoni0]

recently we worked with a team that specified only the provider name in dotnet-trace without keywords/level. dotnet-trace will include ALL keywords on VERBOSE level. this can easily degrade perf. DotNETRuntime provider will also induce GCs (due to the GCHeapCollect keyword).

[Maoni Stephens @maoni0]

@StudentDanLuis the only thing you can specify is that EventCounterIntervalSec filter value

[Maoni Stephens @maoni0]

@StudentDanLuis the name of the runtime counter provider is System.Runtime. this is mentioned here https://t.co/1kISv04Yym albeit not obvious that's the name of the provider.

[Maoni Stephens @maoni0]

@StudentDanLuis logman, eg -

logman query providers Microsoft-Windows-DotNETRuntime

[Maoni Stephens @maoni0]

so really you should specify the keyword/level🙂 or use one of the built-in profiles

[Maoni Stephens @maoni0]

I've requested the diagnostics folks to the change the default: https://t.co/A9KVR2FMDY. note that this means no keywords enabled on informational level.

[Maoni Stephens @maoni0]

@fiigii will definitely keep that in mind. I'll try to find time to do it🙂

[Maoni Stephens @maoni0]

if you use PerfView, have you noticed the GCTriggeredStacks cmd arg? to see callstacks for induced GCs, use this lightweight commandline -

PerfView /GCCollectOnly /GCTriggeredStacks /nogui collect

(this is less verbose than what mem-doc currently shows)

[Maoni Stephens @maoni0]

profiling tip - if you upgrade to a newer version of a product and observe perf regression, make sure to grab some perf traces before you revert (if you revert all usage and can't easily get traces later). without comparative traces the investigation will be much harder

[Maoni Stephens @maoni0]

@fiigii a major problem is interesting data to look at usually isn't shareable publicly. to make it shareable it would require a lot of time (for someone inept at video editing like me) to post process😅

[Maoni Stephens @maoni0]

@chnasarre @konradkokosa @KooKiz also probably better to ask questions like this in email instead of on twitter. in general I look at twitter very infrequently these days (I just happened to look because I made a tweet myself recently)🙂

[Maoni Stephens @maoni0]

@chnasarre @konradkokosa @KooKiz (by expose I just meant expose it directly, because you can calculate it yourself)