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| author | Anthony Liguori <aliguori@us.ibm.com> | 2013-05-03 11:20:15 -0500 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2013-05-03 11:20:16 -0500 |
| commit | 743bddb4b35ceaaf6f95aea581a4130dcae6205a (patch) | |
| tree | eeabd3f7fd008377db4ea3c8152560718fa427f9 /docs | |
| parent | a612925b4184fa7aa37092db4fef816030640922 (diff) | |
| parent | e64dd5efb2c6d522a3bc9d096cd49a4e53f0ae10 (diff) | |
Merge remote-tracking branch 'stefanha/tracing' into staging
# By Eiichi Tsukata (2) and Kazuya Saito (2)
# Via Stefan Hajnoczi
* stefanha/tracing:
trace: document ftrace backend
trace: Add ftrace tracing backend
kvm-all: add kvm_run_exit tracepoint
kvm-all: add kvm_ioctl, kvm_vm_ioctl, kvm_vcpu_ioctl tracepoints
Message-id: 1367582485-15579-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/tracing.txt | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/docs/tracing.txt b/docs/tracing.txt index cf53c173ec..60ff9c5e6e 100644 --- a/docs/tracing.txt +++ b/docs/tracing.txt @@ -175,6 +175,22 @@ unless you have specific needs for more advanced backends. The "simple" backend currently does not capture string arguments, it simply records the char* pointer value instead of the string that is pointed to. +=== Ftrace === + +The "ftrace" backend writes trace data to ftrace marker. This effectively +sends trace events to ftrace ring buffer, and you can compare qemu trace +data and kernel(especially kvm.ko when using KVM) trace data. + +if you use KVM, enable kvm events in ftrace: + + # echo 1 > /sys/kernel/debug/tracing/events/kvm/enable + +After running qemu by root user, you can get the trace: + + # cat /sys/kernel/debug/tracing/trace + +Restriction: "ftrace" backend is restricted to Linux only. + ==== Monitor commands ==== * trace-file on|off|flush|set <path> |