[PATCHV4 0/5] trace-cmd: Support the feature which guests send trace data via virtio

From: Yoshihiro YUNOMAE
Date: Thu Jul 10 2014 - 20:58:38 EST

Hi Steven,

This is a v4 patch set to support the feature which guests send trace data via
virtio. (Previous patch set is here: https://lkml.org/lkml/2013/12/16/688)

Any features in this V4 patch series are not changed from previous version.
I fixed some typos, rebased for current version, and added usage in this

Would you review this patch series?

<How to use>
1. Run virt-server on a host
# trace-cmd virt-server --dom guest1 -c 2

2. Set up of virtio-serial pipe of guest1 on the host
Add the following tags to domain XML files.
# virsh edit guest1
<channel type='unix'>
<source mode='connect' path='/tmp/trace-cmd/virt/agent-ctl-path'/>
<target type='virtio' name='agent-ctl-path'/>
<channel type='pipe'>
<source path='/tmp/trace-cmd/virt/guest1/trace-path-cpu0'/>
<target type='virtio' name='trace-path-cpu0'/>
<channel type='pipe'>
<source path='/tmp/trace-cmd/virt/guest1/trace-path-cpu1'/>
<target type='virtio' name='trace-path-cpu1'/>

3. Boot the guest
# virsh start guest1

4. Run the guest1's client(see trace-cmd-record(1) with the *--virt* option)
# trace-cmd record -e sched* --virt

If you want to boot another guest sends trace-data via virtio-serial,
you will manually make the guest domain directory and trace data I/Fs.

- Make guest domain directory on the host
# mkdir -p /tmp/trace-cmd/virt/<DOMAIN>
# chmod 710 /tmp/trace-cmd/virt/<DOMAIN>
# chgrp qemu /tmp/trace-cmd/virt/<DOMAIN>

- Make FIFO on the host
# mkfifo /tmp/trace-cmd/virt/<DOMAIN>/trace-path-cpu{0,1,...,X}.{in,out}

I measured CPU usage outputted by top command on a guest when client sends
trace data. Client means "record -N"(NW) or "record --virt"(virtio-serial).

NW virtio-serial(splice)
client(fedora19) ~2.9[%] ~1.7[%]

Changes in V4:
[1/5] Fix some typos, cleanup, and rebase for current trace-cmd-v2.4
Change the argument of tracecmd_msg_recv()
[2/5] Fix some typos
Change the argument of tracecmd_msg_recv_wait()
[3/5] Fix some typos and cleanup
[4/5] Introduce parse_args_virt() and add usage of virt-server in trace-usage.c
[5/5] Rebase for current trace-cmd-v2.4 and add usage of --virt for record in
Divide tracecmd_msg_connect_to_server() into two functions
(tracecmd_msg_connect_to_server() and

Changes in V3:
[2/6] Change the license of trace-msg.c to LGPL v2.1
[4/6] Change _nw/_NW to _net/_NET
[5/6] Change _nw/_NW to _net/_NET
[6/6] Add this patch based on Steven's review

Changes in V2:
[1/5] Add a comment in open_udp()
[2/5] Regacy protocol support in order to keep backward compatibility

Thank you,


Yoshihiro YUNOMAE (5):
trace-cmd/listen: Apply the trace-msg protocol for communication between a server and clients
trace-cmd/msg: Use poll(2) to wait for a message
trace-cmd/virt-server: Add virt-server mode for a virtualization environment
trace-cmd/virt-server: Add --dom option which makes a domain directory to virt-server
trace-cmd/record: Add --virt option for record mode

Documentation/trace-cmd-record.1.txt | 11
Documentation/trace-cmd-virt-server.1.txt | 113 ++++
Makefile | 2
trace-cmd.c | 3
trace-cmd.h | 15
trace-listen.c | 717 +++++++++++++++++++-----
trace-msg.c | 873 +++++++++++++++++++++++++++++
trace-msg.h | 31 +
trace-output.c | 4
trace-record.c | 146 ++++-
trace-recorder.c | 50 +-
trace-usage.c | 18 +
12 files changed, 1818 insertions(+), 165 deletions(-)
create mode 100644 Documentation/trace-cmd-virt-server.1.txt
create mode 100644 trace-msg.c
create mode 100644 trace-msg.h

Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: yoshihiro.yunomae.ez@xxxxxxxxxxx
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