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Re: [Qemu-devel] Qemu and CPU wait time
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] Qemu and CPU wait time |
Date: |
Wed, 22 Mar 2017 16:06:37 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
On Mon, Mar 06, 2017 at 03:32:49PM +0100, Peter Lieven wrote:
> is there something equivalent to "CPU ready" in VMWare or „Hyper-V Hypervisor
> Virtual Processor\CPU Wait Time Per Dispatch“ in Hyper-V in
> KVM/Qemu?
I think you can get this information from "perf sched latency" (see man
perf-sched). Restrict it to the vcpu threads and it shows how long a
runnable vcpu has to wait (average and maximum).
Here is an example from https://lwn.net/Articles/353295/:
perf sched record sleep 10 # record full system activity for 10 seconds
perf sched latency --sort max # report latencies sorted by max
-----------------------------------------------------------------------------------------
Task | Runtime ms | Switches | Average delay ms |
Maximum delay ms |
-----------------------------------------------------------------------------------------
python:14049 | 114.694 ms | 125 | avg: 0.120 ms | max:
5.343 ms |
...
-----------------------------------------------------------------------------------------
TOTAL: | 3144.817 ms | 11654 |
---------------------------------------------------
More info: http://www.brendangregg.com/blog/2017-03-16/perf-sched.html
Stefan
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