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8.5 KiB
8.5 KiB
Tested on Fedora25 4.11.3-200.fc25.x86_64, gcc (GCC) 6.3.1 20161221 (Red Hat 6.3.1-1)
As an alternative to using ...bcc/tests/python/include/folly/tracing/StaticTracepoint.h, it's possible to use systemtap-sdt-devel. However, this is not required for this sample.
$ sudo dnf install systemtap-sdt-devel # For Fedora25, other distro's might have differently named packages.
If using systemtap-sdt-devel, the following commands can be used to generate the corresponding header and object files: Also see the CMakeLists.txt file for an example how to do this using cmake.
$ dtrace -h -s usdt_sample_lib1/src/lib1_sdt.d -o usdt_sample_lib1/include/usdt_sample_lib1/lib1_sdt.h
$ dtrace -G -s usdt_sample_lib1/src/lib1_sdt.d -o lib1_sdt.o
Build the sample:
$ pwd
~/src/bcc
$ mkdir -p examples/usdt_sample/build && pushd examples/usdt_sample/build
$ cmake .. && make
$ popd
After building, you should see the available probes:
$ python tools/tplist.py -l examples/usdt_sample/build/usdt_sample_lib1/libusdt_sample_lib1.so
examples/usdt_sample/build/usdt_sample_lib1/libusdt_sample_lib1.so usdt_sample_lib1:operation_end
examples/usdt_sample/build/usdt_sample_lib1/libusdt_sample_lib1.so usdt_sample_lib1:operation_start
$ readelf -n examples/usdt_sample/build/usdt_sample_lib1/libusdt_sample_lib1.so
Displaying notes found at file offset 0x000001c8 with length 0x00000024:
Owner Data size Description
GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: 3930c19f654990159563394669f2ed5281513302
Displaying notes found at file offset 0x0001b9ec with length 0x000000c0:
Owner Data size Description
stapsdt 0x00000047 NT_STAPSDT (SystemTap probe descriptors)
Provider: usdt_sample_lib1
Name: operation_end
Location: 0x000000000000ed6d, Base: 0x0000000000000000, Semaphore: 0x0000000000000000
Arguments: -8@%rbx -8@%rax
stapsdt 0x0000004e NT_STAPSDT (SystemTap probe descriptors)
Provider: usdt_sample_lib1
Name: operation_start
Location: 0x000000000000ee2c, Base: 0x0000000000000000, Semaphore: 0x0000000000000000
Arguments: -8@-24(%rbp) -8@%rax
Start the usdt sample application:
$ examples/usdt_sample/build/usdt_sample_app1/usdt_sample_app1 "pf" 1 30 10 1 50
Applying the following parameters:
Input prefix: pf.
Input range: [1, 30].
Calls Per Second: 10.
Latency range: [1, 50] ms.
You can now run the bcc scripts, see usdt_sample.md for examples.
pid: 25433
Press ctrl-c to exit.
Use argdist.py on the individual probes:
$ sudo python tools/argdist.py -p 25433 -i 5 -C 'u:usdt_sample_lib1:operation_start():char*:arg2#input' -z 32
[11:18:29]
input
COUNT EVENT
1 arg2 = pf_10
1 arg2 = pf_5
1 arg2 = pf_12
1 arg2 = pf_1
1 arg2 = pf_11
1 arg2 = pf_28
1 arg2 = pf_16
1 arg2 = pf_19
1 arg2 = pf_15
1 arg2 = pf_2
2 arg2 = pf_17
2 arg2 = pf_3
2 arg2 = pf_25
2 arg2 = pf_30
2 arg2 = pf_13
2 arg2 = pf_18
2 arg2 = pf_7
2 arg2 = pf_29
2 arg2 = pf_26
3 arg2 = pf_8
3 arg2 = pf_21
3 arg2 = pf_14
4 arg2 = pf_6
4 arg2 = pf_23
5 arg2 = pf_24
Use latency.py to trace the operation latencies:
$ sudo python examples/usdt_sample/scripts/latency.py -p=25433 -f="pf_2"
Attaching probes to pid 25433
Tracing... Hit Ctrl-C to end.
time(s) id input output start (ns) end (ns) duration (us)
0.000000000 7204 pf_28 resp_pf_28 11949439999644 11949489234565 49234
0.100211886 7205 pf_28 resp_pf_28 11949540211530 11949574403064 34191
0.300586675 7207 pf_21 resp_pf_21 11949740586319 11949742773571 2187
0.400774366 7208 pf_28 resp_pf_28 11949840774010 11949859965498 19191
0.701365719 7211 pf_21 resp_pf_21 11950141365363 11950152551131 11185
0.901736620 7213 pf_25 resp_pf_25 11950341736264 11950347924333 6188
1.102162217 7215 pf_21 resp_pf_21 11950542161861 11950567484183 25322
1.302595998 7217 pf_23 resp_pf_23 11950742595642 11950761841242 19245
1.503047601 7219 pf_2 resp_pf_2 11950943047245 11950951213474 8166
1.703371457 7221 pf_27 resp_pf_27 11951143371101 11951176568051 33196
2.104228899 7225 pf_24 resp_pf_24 11951544228543 11951588432769 44204
2.304608175 7227 pf_21 resp_pf_21 11951744607819 11951790796068 46188
2.404796703 7228 pf_21 resp_pf_21 11951844796347 11951877984160 33187
2.605134923 7230 pf_27 resp_pf_27 11952045134567 11952065327660 20193
3.206291642 7236 pf_29 resp_pf_29 11952646291286 11952660443343 14152
3.506887492 7239 pf_21 resp_pf_21 11952946887136 11952995060987 48173
Use lat_dist.py to trace the latency distribution:
$ sudo python examples/usdt_sample/scripts/lat_dist.py -p=25433 -i=30 -f="pf_20"
Attaching probes to pid 25433
[11:23:47]
Bucket ptr = 'pf_20'
latency (us) : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 0 | |
512 -> 1023 : 0 | |
1024 -> 2047 : 1 |********** |
2048 -> 4095 : 1 |********** |
4096 -> 8191 : 0 | |
8192 -> 16383 : 1 |********** |
16384 -> 32767 : 4 |****************************************|
32768 -> 65535 : 3 |****************************** |
Use lat_avg.py to trace the moving average of the latencies:
$ sudo python examples/usdt_sample/scripts/lat_avg.py -p=25433 -i=5 -c=10 -f="pf_2"
Attaching probes to pid 25433
Tracing... Hit Ctrl-C to end.
[11:28:32]
input count latency (us)
pf_22 3 7807
pf_23 4 36914
pf_25 3 31473
pf_28 2 10627
pf_27 1 47174
pf_29 1 8138
pf_26 1 49121
pf_20 2 29158