On Sun, Feb 27, 2011 at 4:14 PM, Avi Kivity <a...@redhat.com> wrote: > On 02/27/2011 04:58 PM, Stefan Hajnoczi wrote: >> >> Trace events outside the global mutex cannot be used with the simple >> trace backend since it is not thread-safe. There is no check to prevent >> them being enabled so people sometimes learn this the hard way. >> >> This patch restructures the simple trace backend with a ring buffer >> suitable for multiple concurrent writers. A writeout thread empties the >> trace buffer when threshold fill levels are reached. Should the >> writeout thread be unable to keep up with trace generation, records will >> simply be dropped. > > It would be good to have an indication of the fact that records were dropped > in the file.
Good idea. Trace files begin with a record that has a special ID. I'll look at extending this either by picking another special ID or by reusing the header record. Stefan
