Re: [PATCH v3 2/3] perf: Userspace event

Hi Pawel,

On Tue,  4 Nov 2014 00:28:37 +0000, Pawel Moll wrote:

+	/*
+	 * Data in userspace event record is transparent for the kernel
+	 *
+	 * Userspace perf tool code maintains a list of known types with
+	 * reference implementations of parsers for the data field.
+	 *
+	 * Overall size of the record (including type and size fields)
+	 * is always aligned to 8 bytes by adding padding after the data.
+	 *
+	 * struct {
+	 *	struct perf_event_header	header;
+	 *	u32				type;
+	 *	u32				size;

The struct perf_event_header also has 'size' field and it has the entire
length of the record so it's redundant.  Also there's 'misc' field in the
perf_event_header and I guess it can be used as 'type' info as it's
mostly for cpumode and we are in user mode by definition.

Thanks,
Namhyung

+	 *	char				data[size];
+	 *	char				__padding[-size & 7];
+	 * 	struct sample_id		sample_id;
+	 * };
+	 */
+	PERF_RECORD_UEVENT			= 11,
+
 	PERF_RECORD_MAX,			/* non-ABI */
 };