Brief introduction to DTrace technologies within OpenSolaris/Solaris 10 and DTrace probes within Apache, PHP and MySQL can provide end to end dynamic tracing of your Drupal based web site..

1. Dynamic Tracing your AMP site Sriram Natarajan Engineer Sun Microsystems Inc

3. Analyze data looking for bottlenecks, trends and correlations.

4. Speculate on remedies

6. Largely new functionality to ask questions.

8. Zero probe effect when Dtrace is not running.

9. Does a fast trap into Dtrace probe to minimize performance impact.

10. A simple Dtrace script #!/usr/sbin/dtrace -qs syscall:::entry { @num[probefunc] = count() }

11. Dtrace format ● provider:module:function:name ● -P provider ● -m module ● -f function ● -n name ● -s script ● -p pid ● -c run command ● -l list ● -v verbose

16. MySQL / PHP Dtrace probes are enabled within engine

17. Fired when execution flow reaches probe location.

18. No overhead for inactive probes.

19. Provide hard to get under the hood information in a simple way.

20. Some performance hit depending on number of probes fired

21. Sample MySQL D Script #!/usr/sbin/dtrace -qs dtrace:::BEGIN { printf("%-40s %2s %-9s", "Query", "QC", "Time(ms)"); } mysql*:::query-start { self->query = copyinstr(arg0); self->querystart = timestamp; self->qc = 0; } mysql*:::query-cache-hit { self->qc = 1; } mysql*:::query-cache-miss { self->qc = 0; } mysql*:::query-done { printf("%-40s %-2s %-9d",self->query,(self->qc ? "Y" : "N"), (timestamp - self->querystart) / 1000000); }

22. Sample MySQL D Script Output select * from t1 order by i limit 10 N 1072 set global query_cache_size=262144 N 0 select * from t1 order by i limit 10 N 781 select * from t1 order by i limit 10 Y 0 select * from t1 order by i limit 30 Y 0 select * from t1 order by i limit 10 Y 0 select * from t1 order by i limit 10 Y 0

23. MySQL Dtrace probes connection-start(id, user, hostname) connection-done(status, id) command-start(id, command_id) command-end(status) query-start(query, id, db, user, host) query-done(status) query-parse-start(query) query-parse-done(status) query-cache-hit(query, row) query-cache-miss(query) query-exec-start(query, id, db, host, exec_type) query-exec-done(status) insert/update/delete-row-start(db, table, status) insert/update/delete-row-done(db, table, status) select/insert/update/multi-update-start(query, status, rows, rowsmatched, rowschanged) select/insert/update/multi-update-done(query, status, rows, rowsmatched, rowschanged)

24. Sample PHP D Script php*:::compile-file-entry /arg0 != NULL/ { self->compile_file = copyinstr(arg0); self->compile_start_time = timestamp; } php*:::compile-file-return /self->compile_file == copyinstr(arg0)/ { self->compile_elapsed = ((timestamp - self->compile_start_time) / 1000000); @compile_time[self->compile_file] = quantize(self->compile_elapsed); self->compile_file = 0; self->compile_file_translated = 0; self->compile_start_time = 0; } tick-60s { printf("Exclusive compile elapsed times,"); printa(" %s, %@d", @compile_time); }

25. PHP Dtrace probes request-startup(request-file, request-uri, request-method) request-end(request-file, request-uri, request-method) compile-file-entry(compile-file, compile-file-translated) compile-file-return(compile-file, compile-file-translated) function-entry(function-name, request-file, lineno, classname, scope) function-end(function-name, request-file, lineno, classname, scope) execute-entry(request-file, lineno) execute-end(request-file, lineno) error(errormsg, request-file, lineno) execption-thrown(classname) exception-catched(classname)

28. To track Object create / destroy life cycle.

30. Apache Dtrace Probes accept_connection(uint*) log_request(uint*, char*, char*) receive_request (uint*) create_child() check_user_credentials(uint*) check_access(uint*) check_authorization(uint*)

32. Apache Dtrace probes are available at http://prefetch.net

33. PHP Dtrace probes are integrated within PHP 6.x source tree.

34. Ruby Dtrace probes are integrated within Ruby source.

36. https://www.opensolaris.org/os/community/dtrace/