Thread: Problem with profiling tool gprof

Hi,
I have a UDP client in C. I need to profile this program. I have used gprof. Now the makefile looks like:

Code:

all: UDPClientProject
#Macro definitions
CC = gcc
CFLAGS = -lm
INCLUDES = -I/usr/include/mysql
LIBS = -L/usr/lib/mysql -lmysqlclient

xTRClient.o: xTRClient.c map_registration.h
	$(CC) $(CFLAGS) -pg -c xTRClient.c

TCP_server_address_db.o: TCP_server_address_db.c map_registration.h
	$(CC) $(CFLAGS) $(INCLUDES) -pg -c TCP_server_address_db.c

UDPClientProject: xTRClient.o TCP_server_address_db.o
	$(CC) -pg -o UDPClientProject xTRClient.o TCP_server_address_db.o $(LIBS)

clean:
	-rm xTRClient.o TCP_server_address_db.o

After the program runs (its a large code, so it takes a while), the output for the profile looks like (important parts are only shown):

Code:

Flat profile:

Each sample counts as 0.01 seconds.
 no time accumulated

  %   cumulative   self              self     total           
 time   seconds   seconds    calls  Ts/call  Ts/call  name    
  0.00      0.00     0.00      100     0.00     0.00  append
  0.00      0.00     0.00        8     0.00     0.00  delete_query
  0.00      0.00     0.00        8     0.00     0.00  get_map_notify_packet
  0.00      0.00     0.00        8     0.00     0.00  insert_query
  0.00      0.00     0.00        8     0.00     0.00  map_notify_packet_initialization
  0.00      0.00     0.00        8     0.00     0.00  map_register_packet_initialization
  0.00      0.00     0.00        8     0.00     0.00  tcp_server_access_main
  0.00      0.00     0.00        1     0.00     0.00  access_file_insert_data

................................

granularity: each sample hit covers 4 byte(s) no time propagated

index % time    self  children    called     name
                0.00    0.00     100/100         access_file_insert_data [8]
[1]      0.0    0.00    0.00     100         append [1]
-----------------------------------------------
                0.00    0.00       8/8           tcp_server_access_main [7]
[2]      0.0    0.00    0.00       8         delete_query [2]
-----------------------------------------------
                0.00    0.00       8/8           main [15]
[3]      0.0    0.00    0.00       8         get_map_notify_packet [3]
-----------------------------------------------
                0.00    0.00       8/8           tcp_server_access_main [7]
[4]      0.0    0.00    0.00       8         insert_query [4]
-----------------------------------------------
                0.00    0.00       8/8           main [15]
[5]      0.0    0.00    0.00       8         map_notify_packet_initialization [5]
-----------------------------------------------
                0.00    0.00       8/8           main [15]
[6]      0.0    0.00    0.00       8         map_register_packet_initialization [6]
-----------------------------------------------
                0.00    0.00       8/8           main [15]
[7]      0.0    0.00    0.00       8         tcp_server_access_main [7]
                0.00    0.00       8/8           delete_query [2]
                0.00    0.00       8/8           insert_query [4]
-----------------------------------------------
                0.00    0.00       1/1           main [15]
[8]      0.0    0.00    0.00       1         access_file_insert_data [8]
                0.00    0.00     100/100         append [1]
-----------------------------------------------

Please tell me if I had done something wrong or not in the makefile.
Most importantly, why are all the time 0.0. The program is large and it takes quite a lot of time. Why am I getting 0.0 instead of the actual time?

Another question is: how do u use gprof with a UDP server program. Because as u know, the UDP server goes into an infinite loop and I have to press CTRL+C to stop. If I stop the program in this way, then gmon.out doesn't get generated. What should I do?

Bye.

By the way, I am using:
Distributor ID: Ubuntu
Description: Ubuntu 10.10
Release: 10.10
Codename: maverick

Originally Posted by Salem

It might be taking a long time, but is all that time being spent in library code?
I mean, 100 calls to append(), which does very little except call some library function isn't going to accumulate enough time of it's own. 0.01 seconds is a long time for a modern CPU.

> the UDP server goes into an infinite loop and I have to press CTRL+C to stop. If I stop the program in this way, then gmon.out doesn't get generated. What should I do?
You need to add a bit of test code to cause it to exit normally, say for example a set period of time after the last client has closed the connection.
Or you send it a special "quit now" message over some interface.
Or you have a signal handler for say SIGUSR1, which internally sets some "quit now" flag (to be tested in your infinite loop), and which you trigger by typing "kill -s USR1 pid" in a console.

Hi, thanks for your reply and idea. But is there any way to get a millisecond or microsecond timing of the program?

Bye.