Mosquitto: Mosquitto v1.5.1 on Windows uses a lot of CPU

[gbr8cke]

On a machine with 2 cores, Mosquitto uses between 40 - 50% CPU of the complete machine. With previous versions, it almost didn't consume any CPU load. I don't think this is normal. Can somebody check this?
Thanks a lot!

[wiebeytec]

How many clients do you have? Because 50% is 100% of one core, I suspect you may be affected by #948.

[gbr8cke]

I don't have a lot of clients. I Publish/Subscribe with max. 5 clients. If I revert to the previous version, I don't have any CPU load - so for me it's really this version that causes the high CPU load.

[gbr8cke]

Does anybody has the same issues on Windows?

[kiranpradeep]

@wiebeytec I downloaded and installed 1.5.1 (64 bit) on Win 10 Home(1803) with Win64OpenSSL v1.1.0i light as dependency. I also installed as service only to see if it crashes. CPU utilization was high at 30% on Core i5. I am sorry, I can't provide logs as I now moved to 1.4.9 to see how it behaves. Please note that I didn't start any clients at all. But this issue exists and is not related to clients.

[toast-uz]

@gbr8cke , @kiranpradeep , could you try only to run "mosquitto.exe -v" on command prompt? I tried it on Win10 Pro(32bit, 1511) on VirtualBox, but the issue was not reproduced. I'will update Windows and retry soon later.

[toast-uz]

I've reproduced after updating to Windows 10 Pro (32bit, 1803). I guess something wrong in mosquitto appeared.

[toast-uz]

p.s.
There are many issues for CPU usage on Windows 10-1803. But, this seems different from them because it occurs while mosquitto runs.

[gbr8cke]

I don't think you have to search this in the Windows 10-1803 direction -> I had the issue on a Windows server 2008 R2. Maybe the verion of the .Net framework? (In my case it was 4.5 and another test with 4.7)

[km3]

Have same problem on Windows with ver. 1.5.1.
On win 10, i3 with 4 core eat 30% of CPU, on win 2016 server with 2 core eat 50% of CPU.
Do not have connection at all.
They don't use .net.
I'm compile it using VC c++, only use vc_redist libs.

[km3]

Check on mosquitto-1.4.15-install-win32 - normal use of CPU: 0%

[KHouse75]

I can confirm that I also have the same 40% to 50% CPU usage with 1.5.1 32 bit and 64 bit running on Windows 7. I switched back to 1.4.15 and it shows 0% CPU.

[saqirltu]

Still experiencing the same with v1.5.2 both on Win7 64 and Win10 64.

[ralight]

This is fixed by the pull request in #971, which will be in 1.5.3 shortly.