4 ms·
Hey, just woke up. I don't see anything wrong here, so I think I will second the other commenter. I wonder if the VMs are over-subscribed? Is there any way to t
by fwsgonzo 6y ago
Hey, just woke up. I don't see anything wrong here, so I think I will second the other commenter. I wonder if the VMs are over-subscribed? Is there any way to tell or would that be a business secret?
I also think we should consider how CPU usage is calculated as well. I don't know how it's done inside VMs, but I can easily imagine that there are several cases where it would include time where the CPU is just waiting for things like access to memory or even waiting on I/O as long as that happens through a shared memory ring buffer, via spinning or something to that effect. So, if that is how it works, then over-subscription of VMs could cause them to show higher CPU usage. But, I don't know, and I hope someone more familiar with the subject will join the discussion.
- pbowyer 6y agoThere's no way to tell if over-subscribed AFAIK. The VM is with UpCloud as I had credits there. I haven't used strace before but I ran it and perf top and have put images at https://twitter.com/peterbowyer/status/1294181276061241344 https://twitter.com/peterbowyer/status/1294181276061241344. The __memset_avx2_erms is present even with 5 concurrent requests (but at 11% overhead then) and the core dump still happens. Very odd.