In general is there any way to get the details of the process (the process to which my program is translated to by the OS before execution). Is it possible to output the contents of the data structures (PCB for example) while my program is executing as a process?
I recommend running the program in linux .. you can then use readlf and objdump to get lot of information about the process(like its address space, dynamically linked libraries from glibc Ex:printf(), its symbol table etc)...
u can also see cat /proc/process's pid folder in linux, there to you can get a variety of information about the running process.
Ofcourse you can use a debugger to get the process's state as it is executing
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I'm interested in the issue related to the MPICH. I know that OpenMPI allows you to run programs using Rankfile. The Rankfile contains information about which node/socket/core the specific rank of the MPI process will be bound to.
Is there the same or similar possibility in MPICH? I mean, every MPI process has to be bound to the core, which I select myself and write in the file.
Thank you!
Is there possibility to show what's going on under specified process in Linux?
For example, i run SQL query -> select evil_function();
and notice that process under Linux uses all cpu.
So is there something with what I can see whats going on under this process?
What I want is to see what queries is running under this process.
Thanks!
strace will tell you what system calls the process is making.
To see what called routines are taking the most CPU, you need to run a profiling tool, and make sure the executable of the process you in compiled correctly (sometimes it needs to be instrumented during compilation for profiling, sometimes it just needs to be compiled with debug symbols, or not stripped of them after compilation).
You might want to look at oprofile, valgrind, gprof and for starters on free tools - there are also commercial products available.
Here are a few links:
http://www.pixelbeat.org/programming/profiling/
http://en.wikipedia.org/wiki/List_of_performance_analysis_tools
You are mixing a whole bunch of things.
If you are talking about MySQL do:
show processlist;
For info specifically about linux processes, you can strace the process to get a list of system function that it calls. Unless you are experienced with linux this will be useless to you.
If the process is paused then you can find out what function it is stopped on, but that's probably not what you want, since you say the process is running.
There are also various tools that can give you info on what parts of the disk the process is reading, and how much memory it's allocating.
And finally you can use gdb to break into the process and single step your way through it to see exactly what it's doing. This will also likely be useless to you since an SQL server does a LOT of things - far to many to understand by this method.
So at work, we check computer's specifications, and need to print these in a standard format. I know how to set up a PXE server already, but I was wondering if it were easy to get a program (or write a script) that will check the computer's hardware (processor, memory, hard drive), and print it over the network.
My thoughts are that I can boot a very simple linux os over PXE, and run a script to do the dirty work. However, I'm not sure how to set it up to use a network printer, or which script to use for that matter.
All the computers have the same architecture, (x86), so a single implementation should work for all of them.
I would be inclined to avoid using a printer directly here and use something like scp or netcat to send back the information you discover.
Edit:
There are a number of tools that might help collecting the data itself, depending on what exactly you want to collect. I've found dmidecode to be very useful. Potientally it can tell you the version of the BIOS, memory stick size/speed/locations and quite a lot of very detailed information. It is buggy on some older hardware with broken DMI tables though. lshal, lshw, lspci and lsusb are all fairly common on linux installations and rather useful for these things.
Have a look at GLPI. It's a good open source software used to manage IT tickets, but, it also integrates a IT infrastructure management that could turn our to be useful in your case.
There is a small piece of software to be installed on each remote client (this could be done remotely and silently) and then you can collect a lot of information and match it by IP addresses
We use 'pdsh' to manage our global network. We have a naming convention of hosts that makes the host expression easy to write. So to continue the ls### suggestion to collect the info on a collection of hardware, we would write a command like this:
[root#admin-console ~]# pdsh -R exec -w china-[1-1024] ssh %h lshal > china-lshal-cabinet-01.log
pdsh prefixes the host name to the output lines and as it runs as a concurrent operator the lines will collate. A simple sorting script using the, say "china-[1-1024]:" tag is needed to get them organized. You could also make the pdsh run sequentially by limiting its concurrency but if you are running large configurations you would want the concurrency.
I am curious to find how does the pstack command prints the stack trace of all the threads running under the PID?
It has to be someway different than the way gdb does since the process runs inside the gdb environment, but pstack is executed after the execution of the process.
It's the same general idea as gdb. pstack uses ptrace, which allows an external process to attach to a known pid and print out the information (stack is known via the current registers).
If you want to know exactly how it's done, look for information about ptrace.
Also, processes don't really run "inside the gdb". You can attach gdb to a running process without much trouble by running gdb executable pid.
pstack print similar output as cat /proc/"pid"/tasks/*/stack so it most likely that it read the procfs rather than using the ptrace.
I want to examine exactly how my code operates when using other libraries to which I do not have the code for. Whilst I can do this online (i.e. with FileMon, RegMon and TCPView from SysInternals), I was wondering if there was a good offline method that would allow me to run up my code in a virtual machine, shutdown the virtual machine and diff the entire VM image?
Since persistent modifications to the system is either in the filesystem on in the registry, you could have a little program that list all the files on the hard drive and also dump the registry.
Then you can also do it after program operation and do a simple file diff.
If you are using virtualbox, I think that you can do the mounting of the disk image offline (i.e. virtual machine not running). However dumping the registry from offline files may be harder.
See "Mount vdi" on google.
All integration testing surely will use code for which you don't have the source, your framework libraries, database drivers, databases, comms libraries. Some of which may not even be on the same machine your code is. I'm not clear exactly what you would hope to achieve. You make some calls to a queueing system, it does all manner of secret squirrel stuff. You diff before and after, now what can you say? Do you know what data formats there ought to be represent your request?
I see tests as being defined in terms of the published behaviours of the libraries and systems I'm working with. Example for a database: I execute some business actions which are supposed to create Orders. I know the orders I defined, do they appear in the database? In defining my tests I can specify explict expected outcomes in terms of records in a database. I can then even automate the tests - compare an extract from the database with expected results.