diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2020-01-31 17:36:59 +0000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2020-01-31 17:37:00 +0000 |
| commit | 28db64fce555a03b4ca256d5b6f4290abdfbd9e8 (patch) | |
| tree | dbf7d5a1e9f85de503956a2ac81327448cc37b82 /docs | |
| parent | aeab8e5eb220cc5ff84b0b68b9afccc611bf0fcd (diff) | |
| parent | e144a605a614d22165000c69e8e1dc6986d45cd8 (diff) | |
Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging
Pull request
# gpg: Signature made Thu 30 Jan 2020 21:38:06 GMT
# gpg: using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg: aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35 775A 9CA4 ABB3 81AB 73C8
* remotes/stefanha/tags/tracing-pull-request:
qemu_set_log_filename: filename argument may be NULL
hw/display/qxl.c: Use trace_event_get_state_backends()
memory.c: Use trace_event_get_state_backends()
docs/devel/tracing.txt: Recommend only trace_event_get_state_backends()
Makefile: Keep trace-events-subdirs ordered
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/devel/tracing.txt | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.txt index 8c0376fefa..cb5f685de9 100644 --- a/docs/devel/tracing.txt +++ b/docs/devel/tracing.txt @@ -342,8 +342,10 @@ edit the "trace-events-all" file). In addition, there might be cases where relatively complex computations must be performed to generate values that are only used as arguments for a trace -function. In these cases you can use the macro 'TRACE_${EVENT_NAME}_ENABLED' to -guard such computations and avoid its compilation when the event is disabled: +function. In these cases you can use 'trace_event_get_state_backends()' to +guard such computations, so they are skipped if the event has been either +compile-time disabled or run-time disabled. If the event is compile-time +disabled, this check will have no performance impact. #include "trace.h" /* needed for trace event prototype */ @@ -356,7 +358,7 @@ guard such computations and avoid its compilation when the event is disabled: align = getpagesize(); } ptr = qemu_memalign(align, size); - if (TRACE_QEMU_VMALLOC_ENABLED) { /* preprocessor macro */ + if (trace_event_get_state_backends(TRACE_QEMU_VMALLOC)) { void *complex; /* some complex computations to produce the 'complex' value */ trace_qemu_vmalloc(size, ptr, complex); @@ -364,10 +366,6 @@ guard such computations and avoid its compilation when the event is disabled: return ptr; } -You can check both if the event has been disabled and is dynamically enabled at -the same time using the 'trace_event_get_state_backends' routine (see header -"trace/control.h" for more information). - === "tcg" === Guest code generated by TCG can be traced by defining an event with the "tcg" |