[Xen-devel] [PATCH v3] xen: make tracebuffer configurable

Baodong Chen posted 1 patch 3 weeks ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/xen tags/patchew/1559698076-17247-1-git-send-email-chenbaodong@mxnavi.com
xen/common/Kconfig      |  9 +++++++++
xen/common/Makefile     |  2 +-
xen/include/xen/trace.h | 26 ++++++++++++++++++++++++++
3 files changed, 36 insertions(+), 1 deletion(-)

[Xen-devel] [PATCH v3] xen: make tracebuffer configurable

Posted by Baodong Chen 3 weeks ago
Xen internal running status(trace event) will be saved to
trace memory when enabled. trace event data and config params can be
read/changed by system control hypercall at run time.

Can be disabled for smaller code footprint.

Signed-off-by: Baodong Chen <chenbaodong@mxnavi.com>
---
 xen/common/Kconfig      |  9 +++++++++
 xen/common/Makefile     |  2 +-
 xen/include/xen/trace.h | 26 ++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index c838506..d908fe1 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -368,4 +368,13 @@ config DOM0_MEM
 
 	  Leave empty if you are not sure what to specify.
 
+config TRACEBUFFER
+	bool "Enable tracing infrastructure"  if EXPERT = "y"
+	default y
+	---help---
+	  Enable in tracing infrastructure and pre-defined tracepoints within Xen.
+	  This will allow live information about Xen’s execution and performance
+	  to be collected at run time for debugging or performance analysis.
+	  Memory and execution overhead when not active is minimal.
+
 endmenu
diff --git a/xen/common/Makefile b/xen/common/Makefile
index bca48e6..9fd1bd2 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -56,7 +56,7 @@ obj-y += sysctl.o
 obj-y += tasklet.o
 obj-y += time.o
 obj-y += timer.o
-obj-y += trace.o
+obj-$(CONFIG_TRACEBUFFER) += trace.o
 obj-y += version.o
 obj-y += virtual_region.o
 obj-y += vm_event.o
diff --git a/xen/include/xen/trace.h b/xen/include/xen/trace.h
index 12966ea..fad92c7 100644
--- a/xen/include/xen/trace.h
+++ b/xen/include/xen/trace.h
@@ -21,12 +21,18 @@
 #ifndef __XEN_TRACE_H__
 #define __XEN_TRACE_H__
 
+/* Put 'tb_init_done' here because 'asm/trace.h' may use it */
+#ifdef CONFIG_TRACEBUFFER
 extern int tb_init_done;
+#else
+#define tb_init_done false
+#endif
 
 #include <public/sysctl.h>
 #include <public/trace.h>
 #include <asm/trace.h>
 
+#ifdef CONFIG_TRACEBUFFER
 /* Used to initialise trace buffer functionality */
 void init_trace_bufs(void);
 
@@ -47,6 +53,26 @@ static inline void trace_var(u32 event, int cycles, int extra,
 void __trace_hypercall(uint32_t event, unsigned long op,
                        const xen_ulong_t *args);
 
+#else
+static inline void init_trace_bufs(void) {}
+static inline int tb_control(struct xen_sysctl_tbuf_op *tbc)
+{
+    return -ENOSYS;
+}
+
+static inline int trace_will_trace_event(uint32_t event)
+{
+    return 0;
+}
+
+static inline void trace_var(uint32_t event, int cycles, int extra,
+                             const void *extra_data) {}
+static inline void __trace_var(uint32_t event, bool cycles, unsigned int extra,
+                               const void *extra_data) {}
+static inline void __trace_hypercall(uint32_t event, unsigned long op,
+                                     const xen_ulong_t *args) {}
+#endif
+
 /* Convenience macros for calling the trace function. */
 #define TRACE_0D(_e)                            \
     do {                                        \
-- 
2.7.4


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

Re: [Xen-devel] [PATCH v3] xen: make tracebuffer configurable

Posted by George Dunlap 2 weeks ago

> On Jun 5, 2019, at 2:27 AM, Baodong Chen <chenbaodong@mxnavi.com> wrote:
> 
> Xen internal running status(trace event) will be saved to
> trace memory when enabled. trace event data and config params can be
> read/changed by system control hypercall at run time.
> 
> Can be disabled for smaller code footprint.
> 
> Signed-off-by: Baodong Chen <chenbaodong@mxnavi.com>
> ---
> xen/common/Kconfig      |  9 +++++++++
> xen/common/Makefile     |  2 +-
> xen/include/xen/trace.h | 26 ++++++++++++++++++++++++++
> 3 files changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/common/Kconfig b/xen/common/Kconfig
> index c838506..d908fe1 100644
> --- a/xen/common/Kconfig
> +++ b/xen/common/Kconfig
> @@ -368,4 +368,13 @@ config DOM0_MEM
> 
> 	  Leave empty if you are not sure what to specify.
> 
> +config TRACEBUFFER
> +	bool "Enable tracing infrastructure"  if EXPERT = "y"
> +	default y
> +	---help---
> +	  Enable in tracing infrastructure and pre-defined tracepoints within Xen.

Sorry, an editing mistake caused me to include a stray ‘in’ in this sentence when I suggested this text. :-)

This could be removed on check-in.  With that fixed, the commit message looks OK to me.

 -George

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

Re: [Xen-devel] [PATCH v3] xen: make tracebuffer configurable

Posted by chenbaodong 2 weeks ago
On 6/5/19 18:38, George Dunlap wrote:
>
>> On Jun 5, 2019, at 2:27 AM, Baodong Chen <chenbaodong@mxnavi.com> wrote:
>>
>> Xen internal running status(trace event) will be saved to
>> trace memory when enabled. trace event data and config params can be
>> read/changed by system control hypercall at run time.
>>
>> Can be disabled for smaller code footprint.
>>
>> Signed-off-by: Baodong Chen <chenbaodong@mxnavi.com>
>> ---
>> xen/common/Kconfig      |  9 +++++++++
>> xen/common/Makefile     |  2 +-
>> xen/include/xen/trace.h | 26 ++++++++++++++++++++++++++
>> 3 files changed, 36 insertions(+), 1 deletion(-)
>>
>> diff --git a/xen/common/Kconfig b/xen/common/Kconfig
>> index c838506..d908fe1 100644
>> --- a/xen/common/Kconfig
>> +++ b/xen/common/Kconfig
>> @@ -368,4 +368,13 @@ config DOM0_MEM
>>
>> 	  Leave empty if you are not sure what to specify.
>>
>> +config TRACEBUFFER
>> +	bool "Enable tracing infrastructure"  if EXPERT = "y"
>> +	default y
>> +	---help---
>> +	  Enable in tracing infrastructure and pre-defined tracepoints within Xen.
> Sorry, an editing mistake caused me to include a stray ‘in’ in this sentence when I suggested this text. :-)
>
> This could be removed on check-in.  With that fixed, the commit message looks OK to me.

Hello George,

sorry for the late reply.

Fixed according to your comments in v4.

>   -George
>

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel