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Re: [Qemu-devel] Patch to add helpful tracing output for driver authors
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation |
Date: |
Fri, 6 Oct 2017 15:01:37 +0100 |
User-agent: |
Mutt/1.9.0 (2017-09-02) |
On Fri, Oct 06, 2017 at 09:58:33AM -0400, Doug Gale wrote:
> I tried to get tracing to work before and I have never gotten it
> working. I'll give it another try and redo the patch with tracing
> infrastructure if necessary. The printf are nice because the dev can
> just look at the terminal where qemu is running. Can you view the
> trace output in realtime? When their code is sitting at a breakpoint
> in their driver, can they see the last thing that was traced right
> there? Or do they have to go run some cumbersome command and wade
> through it after an entire test run after the vm shut down?
There's a variety of trace backends available. By default QEMU enables
the 'log' backend these days. So with a default build of QEMU you can
use the '-d' arg to turn on printing: eg.:
qemu-system-x86_64 ...args... -d trace:qio*
and that'll turn on every tracepoint with 'qio' as a prefix. The
trace messages will be printed straight to the console. eg:
$ qemu-system-x86_64 -d trace:qio* -serial unix:/tmp/foo,server
address@hidden:qio_channel_socket_new Socket new ioc=0x5598b0565d60
address@hidden:qio_channel_socket_listen_sync Socket listen sync
ioc=0x5598b0565d60 addr=0x5598b0565c50
address@hidden:qio_channel_socket_listen_complete Socket listen complete
ioc=0x5598b0565d60 fd=16
qemu-system-x86_64: -serial unix:/tmp/foo,server: info: QEMU waiting for
connection on: disconnected:unix:/tmp/foo,server
address@hidden:qio_channel_socket_new Socket new ioc=0x5598b0564060
address@hidden:qio_channel_socket_accept Socket accept start ioc=0x5598b0565d60
Regards,
Daniel
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- [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Doug Gale, 2017/10/05
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Kevin Wolf, 2017/10/06
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Eric Blake, 2017/10/06
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Daniel P. Berrange, 2017/10/06
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Doug Gale, 2017/10/06
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation,
Daniel P. Berrange <=
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Doug Gale, 2017/10/07
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Eric Blake, 2017/10/09
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Doug Gale, 2017/10/09
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Markus Armbruster, 2017/10/10
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Kevin Wolf, 2017/10/10
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Doug Gale, 2017/10/11
- Re: [Qemu-devel] Patch to add helpful tracing output for driver authors in NVMe emulation, Peter Maydell, 2017/10/11
- Re: [Qemu-devel] [Qemu-block] Patch to add helpful tracing output for driver authors in NVMe emulation, Paolo Bonzini, 2017/10/11