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Sorry to interrupt!
When I use the './trace' command, I get an error:

Error:
cycles:u: PMU Hardware doesn't support sampling/overflow-interrupts.try 'perf stat'.
Then subsequent commands (including perf2bolt, bolt, etc.) fail to execute

Do I need to change the perf command, will it affect the performance of my ocolos? Or do I need to do something else? Maybe my computer doesn't support it?

After running the program and comparing it, I found that the performance has hardly improved. Could you please help me find out the reason?
When I looked at the data from the runtime console, I noticed several suspicious things:

1. BOLT-WARNING: split function detected on input : _ZL28delete_dictionary_tablespacev.cold/1. The support is limited in relocation mode.
2. PERF2BOLT: wrote 16614 objects and 0 memory objects to /home/lyf/Desktop/ocolos-data/perf.fdata
   I looked at the sysbench_output.txt file and found that the performance dropped after 20 seconds and improved again after 130 minutes, but the performance was the same as when I started：
   [ 4s ] thds: 16 tps: 2787.88 qps: 33449.53 (r/w/o: 27874.77/0.00/5574.75) lat (ms,95%): 8.90 err/s: 0.00 reconn/s: 0.00
   [ 26s ] thds: 16 tps: 1918.98 qps: 23029.77 (r/w/o: 19191.81/0.00/3837.96) lat (ms,95%): 12.08 err/s: 0.00 reconn/s: 0.00
   [ 167s ] thds: 16 tps: 2628.97 qps: 31538.64 (r/w/o: 26280.70/0.00/5257.94) lat (ms,95%): 8.74 err/s: 0.00 reconn/s: 0.00
   I have added these two files to the attachment.
   Hope to get your help.
   sysbench_output.txt
   runtime_console_infomation.txt

I modified the MySQL part of this project into MongoDB, including files such as config, src/utils.cpp, src/infrastructure.cpp and src/tracer.cpp, and used YCSB to drive MongoDB for testing. The following error occurs when executing the ./tracer command:
[tracer][error] thread 2129 delivers a non-SIGSTOP signal
[tracer][error] tracee exits normally, exit num = 1

The full console output is as follows:
error.txt

Hope to get your help, thank you!

I have used the extract_call_sites to produced the call site information successfully, but the tracer doesn't work normally with the error “thread 87732 delivers a non-SIGSTOP signal” and "ERROR: couldn't find symbol for function address 0x20520f0". The complete output is shown in the link below:

https://github.com/onroadmuwl/ocolos_tracer_error/blob/main/tracer.out

Any way to fix that?
Thanks.

I have built this target binary, but when I use it to generate call_sites_all.bin file ,it always get nothing. I saw the standard output get the call site infomation, but it didn't write into this file. That made me so confused. The standard output looks like this.

....
00000000042996b0 0000000000000030 B _ZN53protobuf_replication_asynchronous_connection_failover33_VariableStatus_default_instance_E

00000000042996e0 0000000000000040 B _ZN53protobuf_replication_asynchronous_connection_failover37_VariableStatusList_default_instance_E

0000000004299720 0000000000000080 B _ZN53protobuf_replication_asynchronous_connection_failover48_SourceAndManagedAndStatusList_default_instance_E

[extract_call_sites] 61186 functions in the original binary
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
the size of call_sites = 0
@@@@@@@@@@@@ the size of call_sites (final) = 0
########### the size of call_sites_list = 0

Who can tell why? Thanks

I am trying to understand the detailed process of ocolos's code replacement, but I am unable to reach the insert_machine_code() function through GDB. Would you like to guide me through the general steps of debugging replace_function.so? Here's what I've tried so far:

1. I added -DDEBUG to the CPPFLAGS and ran the tracer program. The program ran successfully, and I received the following output:

[tracer] thread id = 1236504, rip = 7f8dd628b99f
[tracer] before SINGLESTEP, set RIP = 7f8dd6b0be1c (lib addr)
[tracer] receive SIGSTOP from tracee (lib code), tracee finished a SINGLESTEP!
[tracer] after SINGLESTEP, RIP = 7f8dd6b0be1b

[tracer] thread id = 1236508, rip = 7f8dd629173d
[tracer] before SINGLESTEP, set RIP = 7f8dd6b0be1c (lib addr)
[tracer] receive SIGSTOP from tracee (lib code), tracee finished a SINGLESTEP!
[tracer] after SINGLESTEP, RIP = 7f8dd6b0be20
[tracer] after a PTRACE_SINGLESTEP, do a PTRACE_CONT
[tracer] connection from 127.0.0.1
[tracer] after PTRACE_CONT, tracee delivers a signal Stopped (signal)
[tracer] RIP = 7f8dd66cd289
[tracer] machine code insertion finishes!
[tracer][time] machine code insertion took 2.071340 seconds to execute
[tracer][OK] code replacement done!

2. Next, I tried to attach the thread using "gdb attach 1236508" and set a breakpoint using "b insert_machine_code". The output I received was "Program received signal SIGSTOP, Stopped (signal)."

(gdb) b insert_machine_code
Breakpoint 1 at 0x7f8dd6b0be1c
(gdb) continue
Continuing.

Program received signal SIGSTOP, Stopped (signal).
syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
38 in ../sysdeps/unix/sysv/linux/x86_64/syscall.S

3. Lastly, I tried the following methods to resolve the issue, but GDB did not output anything for me:

(gdb) b insert_machine_code
Breakpoint 1 at 0x7f8dd6b0be1c
(gdb) handle SIGSTOP nopass
Signal Stop Print Pass to program Description
SIGSTOP Yes Yes No Stopped (signal)
(gdb) handle SIGSTOP nostop
Signal Stop Print Pass to program Description
SIGSTOP No Yes No Stopped (signal)
(gdb) continue
Continuing.

(gdb) b insert_machine_code
Breakpoint 1 at 0x7f8dd6b0be1c
(gdb) shell kill -CONT 1236504
(gdb) continue
Continuing.

May I ask you how you usually debug and understand the code inside “replace_function.so”?