| Demonstrations of funccount, the Linux eBPF/bcc version. |
| |
| |
| This program traces functions, tracepoints, or USDT probes that match a |
| specified pattern, and when Ctrl-C is hit prints a summary of their count |
| while tracing. Eg, tracing all kernel functions that begin with "vfs_": |
| |
| # ./funccount 'vfs_*' |
| Tracing... Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| vfs_create 1 |
| vfs_rename 1 |
| vfs_fsync_range 2 |
| vfs_lock_file 30 |
| vfs_fstatat 152 |
| vfs_fstat 154 |
| vfs_write 166 |
| vfs_getattr_nosec 262 |
| vfs_getattr 262 |
| vfs_open 264 |
| vfs_read 470 |
| Detaching... |
| |
| The above output shows that while tracing the vfs_read() function was called 470 |
| times, and vfs_open() 264 times, etc. |
| |
| This is useful for exploring kernel code, to figure out which functions are in |
| use and which are not. This can narrow down an investigation to just a few |
| functions, whose counts are similar to the workload investigated. |
| |
| |
| Tracing all tcp functions: |
| |
| # ./funccount 'tcp_*' |
| Tracing... Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| tcp_try_undo_recovery 1 |
| tcp_twsk_destructor 1 |
| tcp_enter_recovery 1 |
| tcp_xmit_retransmit_queue 1 |
| tcp_update_scoreboard 1 |
| tcp_verify_retransmit_hint 1 |
| tcp_tsq_handler.part.31 1 |
| tcp_sacktag_write_queue 1 |
| tcp_match_skb_to_sack 1 |
| tcp_time_wait 1 |
| tcp_mark_head_lost 1 |
| tcp_init_cwnd_reduction 1 |
| tcp_sacktag_one 1 |
| tcp_sacktag_walk 1 |
| tcp_retransmit_skb 1 |
| tcp_tasklet_func 1 |
| tcp_resume_early_retransmit 1 |
| tcp_dsack_set 1 |
| tcp_v4_syn_recv_sock 2 |
| tcp_ca_openreq_child 2 |
| tcp_try_fastopen 2 |
| tcp_openreq_init_rwin 2 |
| tcp_v4_init_req 2 |
| tcp_create_openreq_child 2 |
| tcp_v4_send_synack 2 |
| tcp_v4_init_sequence 2 |
| tcp_fragment 2 |
| tcp_v4_conn_request 2 |
| tcp_conn_request 2 |
| tcp_v4_route_req 2 |
| tcp_fragment_tstamp 2 |
| tcp_try_keep_open 2 |
| tcp_v4_reqsk_destructor 2 |
| tcp_may_send_now 2 |
| tcp_make_synack 2 |
| tcp_child_process 2 |
| tcp_check_req 2 |
| tcp_fastretrans_alert 2 |
| tcp_set_keepalive 2 |
| tcp_finish_connect 3 |
| tcp_connect_queue_skb 3 |
| tcp_v4_connect 3 |
| tcp_init_sock 3 |
| tcp_v4_init_sock 3 |
| tcp_connect 3 |
| tcp_any_retrans_done.part.35 3 |
| tcp_clear_retrans 3 |
| tcp_setsockopt 4 |
| tcp_update_metrics 5 |
| tcp_done 5 |
| tcp_initialize_rcv_mss 5 |
| tcp_sndbuf_expand 5 |
| tcp_fin 5 |
| tcp_init_xmit_timers 5 |
| tcp_close 5 |
| tcp_init_congestion_control 5 |
| tcp_init_metrics 5 |
| tcp_gro_complete 5 |
| tcp_free_fastopen_req 5 |
| tcp_v4_destroy_sock 5 |
| tcp_cleanup_congestion_control 5 |
| tcp_send_fin 5 |
| tcp_init_buffer_space 5 |
| tcp_init_cwnd 5 |
| tcp_select_initial_window 5 |
| tcp_check_oom 5 |
| tcp_default_init_rwnd 5 |
| tcp_assign_congestion_control 5 |
| tcp_getsockopt 6 |
| tcp_ioctl 6 |
| tcp_mtup_init 8 |
| tcp_parse_options 8 |
| tcp_mss_to_mtu 8 |
| tcp_try_rmem_schedule 8 |
| tcp_get_metrics 10 |
| tcp_try_coalesce 10 |
| tcp_rcv_state_process 14 |
| tcp_sync_mss 14 |
| tcp_write_timer_handler 15 |
| tcp_write_timer 16 |
| tcp_grow_window.isra.27 22 |
| tcp_set_state 23 |
| tcp_send_ack 37 |
| tcp_delack_timer 42 |
| tcp_delack_timer_handler 42 |
| tcp_validate_incoming 91 |
| tcp_prequeue_process 112 |
| tcp_v4_early_demux 117 |
| tcp_gro_receive 146 |
| tcp_queue_rcv 167 |
| tcp_data_queue 215 |
| tcp_urg 219 |
| tcp_send_delayed_ack 257 |
| tcp_send_mss 275 |
| tcp_push 275 |
| tcp_sendmsg 275 |
| tcp_event_data_recv 275 |
| tcp_nagle_check 279 |
| tcp_write_xmit 282 |
| tcp_event_new_data_sent 282 |
| tcp_current_mss 284 |
| tcp_init_tso_segs 284 |
| tcp_wfree 286 |
| tcp_schedule_loss_probe 305 |
| tcp_v4_send_check 323 |
| tcp_transmit_skb 323 |
| tcp_recvmsg 323 |
| tcp_options_write 325 |
| tcp_rcv_space_adjust 328 |
| tcp_check_space 332 |
| tcp_rcv_established 337 |
| tcp_ack 337 |
| tcp_parse_aligned_timestamp.part.43 345 |
| tcp_prequeue 346 |
| tcp_v4_do_rcv 351 |
| tcp_v4_rcv 351 |
| tcp_parse_md5sig_option 351 |
| tcp_cleanup_rbuf 436 |
| tcp_poll 468 |
| tcp_established_options 604 |
| tcp_v4_md5_lookup 615 |
| tcp_release_cb 736 |
| tcp_rearm_rto 843 |
| tcp_md5_do_lookup 968 |
| Detaching... |
| |
| The current implementation can take many seconds to detach from tracing, after |
| Ctrl-C has been hit. |
| |
| |
| User functions can be traced in executables or libraries, and per-process |
| filtering is allowed: |
| |
| # ./funccount -p 1442 /home/ubuntu/contentions:* |
| Tracing 15 functions for "/home/ubuntu/contentions:*"... Hit Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| main 1 |
| _start 1 |
| primes_thread 2 |
| insert_result 87186 |
| is_prime 1252772 |
| Detaching... |
| |
| If /home/ubuntu is in the $PATH, then the following command will also work: |
| |
| # ./funccount -p 1442 contentions:* |
| |
| |
| Counting libc write and read calls using regular expression syntax (-r): |
| |
| # ./funccount -r 'c:(write|read)$' |
| Tracing 2 functions for "c:(write|read)$"... Hit Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| read 2 |
| write 4 |
| Detaching... |
| |
| |
| Kernel tracepoints are also available as targets. For example, trace common |
| block I/O tracepoints and see how often they are invoked: |
| |
| # ./funccount t:block:* |
| Tracing 19 functions for "t:block:*"... Hit Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| block:block_rq_complete 7 |
| block:block_rq_issue 7 |
| block:block_getrq 7 |
| block:block_rq_insert 7 |
| Detaching... |
| |
| |
| Likewise, user-mode statically defined traces (USDT) can also be probed. For |
| example, count mutex-related events in pthreads: |
| |
| # ./funccount u:pthread:*mutex* -p 1442 |
| Tracing 7 functions for "u:pthread:*mutex*"... Hit Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| mutex_init 1 |
| mutex_entry 547122 |
| mutex_acquired 547175 |
| mutex_release 547185 |
| Detaching... |
| |
| |
| An interval can be provided. Eg, printing output every 1 second for vfs calls: |
| |
| # ./funccount -i 1 'vfs_*' |
| Tracing... Ctrl-C to end. |
| |
| FUNC COUNT |
| vfs_fstatat 1 |
| vfs_fstat 16 |
| vfs_getattr_nosec 17 |
| vfs_getattr 17 |
| vfs_write 52 |
| vfs_read 79 |
| vfs_open 98 |
| |
| FUNC COUNT |
| vfs_fstatat 10 |
| vfs_fstat 10 |
| vfs_open 13 |
| vfs_getattr_nosec 20 |
| vfs_getattr 20 |
| vfs_write 28 |
| vfs_read 39 |
| |
| FUNC COUNT |
| vfs_fsync_range 2 |
| vfs_lock_file 30 |
| vfs_write 107 |
| vfs_fstatat 129 |
| vfs_fstat 130 |
| vfs_open 154 |
| vfs_getattr_nosec 222 |
| vfs_getattr 222 |
| vfs_read 384 |
| ^C |
| Detaching... |
| |
| This can be useful for making some ad hoc tools, exposing new counts of |
| kernel activity that aren't visible in other metrics. |
| |
| Include -T to print timestamps on output. |
| |
| |
| A maximum duration can be set. For example, to print 5 x 1 second summaries |
| of vfs_read() calls: |
| |
| # ./funccount -i 1 -d 5 vfs_read |
| Tracing 1 functions for "vfs_read"... Hit Ctrl-C to end. |
| |
| FUNC COUNT |
| vfs_read 30 |
| |
| FUNC COUNT |
| vfs_read 26 |
| |
| FUNC COUNT |
| vfs_read 54 |
| |
| FUNC COUNT |
| vfs_read 25 |
| |
| FUNC COUNT |
| vfs_read 31 |
| Detaching... |
| |
| By leaving off the "-i 1", this will print a single 5 second summary: |
| |
| # funccount.py -d 5 vfs_read |
| Tracing 1 functions for "vfs_read"... Hit Ctrl-C to end. |
| |
| FUNC COUNT |
| vfs_read 167 |
| Detaching... |
| |
| This can be useful for finding out rates: trace all functions for ten seconds |
| and then divide by ten for the per-second rate. |
| |
| |
| The "*" wildcard can be used multiple times. Eg, matching functions that contain |
| the word "readdir": |
| |
| # ./funccount '*readdir*' |
| Tracing... Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| ext4_readdir 4 |
| Detaching... |
| |
| Matching "tcp" then "send": |
| |
| # ./funccount '*tcp*send*' |
| Tracing... Ctrl-C to end. |
| ^C |
| FUNC COUNT |
| tcp_send_ack 4 |
| tcp_send_delayed_ack 19 |
| tcp_send_mss 26 |
| tcp_sendmsg 26 |
| tcp_v4_send_check 30 |
| __tcp_v4_send_check 30 |
| Detaching... |
| |
| |
| Full USAGE: |
| |
| # ./funccount -h |
| usage: funccount [-h] [-p PID] [-i INTERVAL] [-d DURATION] [-T] [-r] [-D] |
| pattern |
| |
| Count functions, tracepoints, and USDT probes |
| |
| positional arguments: |
| pattern search expression for events |
| |
| optional arguments: |
| -h, --help show this help message and exit |
| -p PID, --pid PID trace this PID only |
| -i INTERVAL, --interval INTERVAL |
| summary interval, seconds |
| -d DURATION, --duration DURATION |
| total duration of trace, seconds |
| -T, --timestamp include timestamp on output |
| -r, --regexp use regular expressions. Default is "*" wildcards |
| only. |
| -D, --debug print BPF program before starting (for debugging |
| purposes) |
| |
| examples: |
| ./funccount 'vfs_*' # count kernel fns starting with "vfs" |
| ./funccount -r '^vfs.*' # same as above, using regular expressions |
| ./funccount -Ti 5 'vfs_*' # output every 5 seconds, with timestamps |
| ./funccount -d 10 'vfs_*' # trace for 10 seconds only |
| ./funccount -p 185 'vfs_*' # count vfs calls for PID 181 only |
| ./funccount t:sched:sched_fork # count calls to the sched_fork tracepoint |
| ./funccount -p 185 u:node:gc* # count all GC USDT probes in node, PID 185 |
| ./funccount c:malloc # count all malloc() calls in libc |
| ./funccount go:os.* # count all "os.*" calls in libgo |
| ./funccount -p 185 go:os.* # count all "os.*" calls in libgo, PID 185 |
| ./funccount ./test:read* # count "read*" calls in the ./test binary |
