Incredibly slow compared to any other JVM about jetbrainsruntime

[prof7bit]

I found an obvious hint while watching the CPU utilization during startup:

with OpenJDK all 4 cores are nearly maxed out continuously the entire time until the IDE is started.

with JetBrains after the splash screen when the empty IDE window appears and the small progress dialog in the middle appears all cores except one drop to zero and only one thread keeps running at 100%.

The total time burnt by the the java process during startup (as reported by htop in the TIME+ column) is almost identical (52 seconds for OpenJDK vs 56 seconds JetBrains) despite JetBrains running more than twice as long until it is finished.

[bulenkov]

@prof7bit How did you measure this? It would be very helpful if you provide some specific scenarios to reproduce the performance problem.

[prof7bit]

• Download and unzip PyCharm (or possibly any other IDE that comes bundled with this runtime)
• start it and note the extreme slowness (the time it takes to start, the sluggish UI, etc)
• configure it to use ANY other JRE you have installed on your system (in my case I tried it with 3 different ones)
• start it again and note the extreme difference. It will become immediately obvious.

I observed this on two different PCs, one has Kubuntu 20.4 and one that has Kubuntu 20.10.

[bulenkov]

We will take a look at Kubuntu, thanks. It looks like a temporary problem. To identify it faster, could you please take a CPU snapshot and send it to us? https://intellij-support.jetbrains.com/hc/en-us/articles/207241235-Reporting-performance-problems

[prof7bit]

I just took the time it takes to start up to a defined state. The IDE has two editor windows open side by side and a terminal in the bottom. I took the time it takes from starting the IDE until the prompt appears in the terminal:

around 14 seconds with Ubuntu OpenJDK and 42 seconds with JetBrains:

PyCharm 2020.3.3 (Community Edition)
Build #PC-203.7148.72, built on January 27, 2021
Runtime version: 15+36-Ubuntu-1 amd64
VM: OpenJDK 64-Bit Server VM by Private Build

14:43
13:89
13:96
15:23

PyCharm 2020.3.3 (Community Edition)
Build #PC-203.7148.72, built on January 27, 2021
Runtime version: 11.0.9.1+11-b1145.77 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.

42:02
42:55
41:17
42:28

---

I'm going to post the CPU snapshot as you suggested in a few minutes...

Edit: I can't find this option in PyCharm :-(

[prof7bit]

Sorry, I can't find anything about "CPU snapshot" anywhere in PyCharm. All I can see is a zip with tons of logs ("collect diagnostic data"), is that what you mean?

[bulenkov]

It should be in your home dir.

Here is a step by step instruction: https://intellij-support.jetbrains.com/hc/en-us/articles/207241235-Reporting-performance-problems#CPU_Snapshot_2019_2

[prof7bit]

This is funny: The screenshot you provided above is nowhere to be found on the link you gave, even a google search for the words "community editions do not bundle performance testing plugin" will give me a link to this website but when I click on it it does not show the above text anywhere that mentions I need a plugin.

I'm going to install the plugin and try to see if I can get these snapshots.

[prof7bit]

Upload id: 2021_02_15_LpjLx36AsBRjTtue

(files: fast-with-openjdk-11-PC-203.7148.72_bernd_15.02.2021_10.55.57.zip,
slow-with-jetbrains-PC-203.7148.72_bernd_15.02.2021_10.59.46.zip)

Now I am sitting on my work PC in the office and my startup times are:
23:44 with JetBrains
08:56 with Ubuntu OpenJDK-11

I followed the "profile slow startup" instructions and generated two snapshots, one with the original JVM and one with Ubuntu OpenJDK.

[prof7bit]

It happens on two Kubuntu machines (even when running an Openbox session without any KDE at all)
It does NOT happen on a Windows 7 VM
It does NOT happen on a Lubuntu 20.4 VM

I removed ~/.local/share/JetBrains and ~/.config/Jetbrains and downloaded and uzipped a fresh copy of pyCharm and it STILL happens on my Kubuntu machine.

Same effect with a fresh install if IntelliJ IDEA and an empty project (this PC has never seen IDEA before), 16 seconds with JetBrains runtime and 7 seconds with OpenJDK.

Could you already have a look at the snapshot files what is causing this? Is there a tool available so I can look at it too?

[avu]

@prof7bit do you still experience this issue (with the latest versions of our products)?