3 ms·

This is my VCL: https://gist.github.com/pbowyer/8822ab1d61fc209056f0f6bc694319f7 https://gist.github.com/pbowyer/8822ab1d61fc209056f0f6bc6943... And how Varnis

This is my VCL: https://gist.github.com/pbowyer/8822ab1d61fc209056f0f6bc694319f7 https://gist.github.com/pbowyer/8822ab1d61fc209056f0f6bc6943... And how Varnish is initialised ExecStart=/usr/sbin/varnishd -a :80 -a 127.0.0.1:6081,PROXY -f /etc/varnish/default.vcl -s malloc,64m -p feature=+http2 I've verified everything is a cache hit, and the ratio is 1.000 by the end of testing. Screenshots and more in this thread: https://twitter.com/peterbowyer/status/1292765478100795393 https://twitter.com/peterbowyer/status/1292765478100795393

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 ago
  There'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.

3 ms·

This is my VCL: https://gist.github.com/pbowyer/8822ab1d61fc209056f0f6bc694319f7 https://gist.github.com/pbowyer/8822ab1d61fc209056f0f6bc6943... And how Varnis

by pbowyer 6y ago

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 ago
  There'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.