Here is some more detailed output from another run, in which clearly the profiled body is taking longer than the sample interval to execute, but fewer samples are taken than expected: > (sb-sprof:with-profiling (:max-samples 2000 :report :flat :loop nil) (time (restore-sheets))) Evaluation took: 22.683 seconds of real time 26.197599 seconds of total run time (14.495562 user, 11.702037 system) [ Run times consist of 5.090 seconds GC time, and 21.108 seconds non-GC time. ] 115.50% CPU 45,252,381,684 processor cycles 65 page faults 1,163,395,360 bytes consed Number of samples: 2 Sample interval: 0.01 seconds Total sampling time: 0.02 seconds Number of cycles: 0 Sampled threads: # Self Total Cumul Nr Count % Count % Count % Calls Function ------------------------------------------------------------------------ 1 1 50.0 1 50.0 1 50.0 - "foreign function getattrlist" 2 1 50.0 1 50.0 2 100.0 - (FLET #:CLEANUP-FUN-[FORM-FUN-[RELEASE-FD-STREAM-RESOURCES]1153]1161) 3 0 0.0 2 100.0 2 100.0 1 RESTORE-SHEETS 4 0 0.0 2 100.0 2 100.0 - SB-EXT:CALL-WITH-TIMING 5 0 0.0 2 100.0 2 100.0 - "Unknown component: #x1004DFB230" 6 0 0.0 2 100.0 2 100.0 - SB-INT:SIMPLE-EVAL-IN-LEXENV 7 0 0.0 2 100.0 2 100.0 - SWANK::EVAL-REGION 8 0 0.0 2 100.0 2 100.0 - "Unknown component: #x10054130D0" 9 0 0.0 2 100.0 2 100.0 - SWANK::TRACK-PACKAGE 10 0 0.0 2 100.0 2 100.0 - SWANK::CALL-WITH-RETRY-RESTART 11 0 0.0 2 100.0 2 100.0 - SWANK::CALL-WITH-BUFFER-SYNTAX 12 0 0.0 2 100.0 2 100.0 - SWANK::REPL-EVAL 13 0 0.0 2 100.0 2 100.0 - SWANK::EVAL-FOR-EMACS 14 0 0.0 2 100.0 2 100.0 - SWANK::PROCESS-REQUESTS 15 0 0.0 2 100.0 2 100.0 - "Unknown component: #x10044F60E0" 16 0 0.0 2 100.0 2 100.0 - SWANK-BACKEND::CALL-WITH-BREAK-HOOK 17 0 0.0 2 100.0 2 100.0 - (FLET SWANK-BACKEND:CALL-WITH-DEBUGGER-HOOK) 18 0 0.0 2 100.0 2 100.0 - SWANK::CALL-WITH-BINDINGS 19 0 0.0 2 100.0 2 100.0 - SWANK::CALL-WITH-CONNECTION 20 0 0.0 2 100.0 2 100.0 - SWANK::HANDLE-REQUESTS 21 0 0.0 2 100.0 2 100.0 - (FLET #:WITHOUT-INTERRUPTS-BODY-[BLOCK391]396) 22 0 0.0 2 100.0 2 100.0 - (FLET SB-THREAD::WITH-MUTEX-THUNK) 23 0 0.0 2 100.0 2 100.0 - (FLET #:WITHOUT-INTERRUPTS-BODY-[CALL-WITH-MUTEX]293) 24 0 0.0 2 100.0 2 100.0 - SB-THREAD::CALL-WITH-MUTEX 25 0 0.0 2 100.0 2 100.0 - SB-THREAD::INITIAL-THREAD-FUNCTION 26 0 0.0 2 100.0 2 100.0 - "foreign function call_into_lisp" 27 0 0.0 2 100.0 2 100.0 - "foreign function new_thread_trampoline" 28 0 0.0 2 100.0 2 100.0 - "foreign function _pthread_start" 29 0 0.0 2 100.0 2 100.0 - "foreign function thread_start" 30 0 0.0 1 50.0 2 100.0 - "foreign function sb_realpath" 31 0 0.0 1 50.0 2 100.0 - SB-UNIX:UNIX-REALPATH 32 0 0.0 1 50.0 2 100.0 - SB-IMPL::MAP-DIRECTORY 33 0 0.0 1 50.0 2 100.0 - (LAMBDA (PATHNAME)) 34 0 0.0 1 50.0 2 100.0 - (FLET SB-IMPL::ITERATE) 35 0 0.0 1 50.0 2 100.0 - SB-IMPL::CALL-WITH-NATIVE-DIRECTORY-ITERATOR 36 0 0.0 1 50.0 2 100.0 - SB-IMPL::MAP-MATCHING-DIRECTORIES 37 0 0.0 1 50.0 2 100.0 - DIRECTORY 38 0 0.0 1 50.0 2 100.0 - SB-IMPL::RELEASE-FD-STREAM-RESOURCES 39 0 0.0 1 50.0 2 100.0 - (SB-PCL::FAST-METHOD SB-GRAY::PCL-CLOSE (SB-KERNEL:ANSI-STREAM)) 40 0 0.0 1 50.0 2 100.0 - (FLET #:CLEANUP-FUN-[EXIT-TAG-[RESTORE]342]350) 41 0 0.0 1 50.0 2 100.0 5298 RESTORE ------------------------------------------------------------------------ 0 0.0 elsewhere #