On 11/29/2011 06:26 PM, Stefan Hajnoczi wrote:
On Tue, Nov 29, 2011 at 12:35 PM, Markus Armbruster<arm...@redhat.com> wrote:
Stefan Hajnoczi<stefa...@gmail.com> writes:
[...]
So forget I said "self-describing" :). I think the only changes from
the v1 format we need are:
1. New magic number to mark v2 format.
2. Trace records are no longer fixed-length, they include a size field:
typedef struct {
uint32_t length; /* in bytes */
uint32_t reserved; /* unused */
uint64_t event;
uint64_t timestamp_ns;
uint8_t arguments[];
} TraceRecord;
3. Strings are serialized like this:
uint16_t length;
char chars[length];
16 bit length? Sure you want that?
You're right, it's more future-proof to use a larger type. Since I
said uint32_t length in TraceRecord, uint32_t here would work well.
Makes sense to store size info only for strings as long as we rely on
trace-events file to identify other meta-data about trace-events.
thanks,
Harsh
Stefan
