#StackBounty: #linux #time #c++ #profiling How to profile wall-clock time?

Bounty: 200

In my program , real time sometimes is as much as 3 times of cpu time. This is a single thread application that does a lot of memory allocation and NFS base read/write. So my doubt is that it is either mem-swap or NFS read-write that is slowing things down.
For example, the following is the output of

% /usr/bin/time a.out
2165.32user 64.93system 6036.33elapsed

Is there any profiling tool for real time ? I know and have used multiple tools for cpu time profiling, but am not sure if there is anything that can help and point out NFS/ mem-swap or any other wall clock slowdowns.

My program is written in C++

EDIT : /usr/bin/time gives me a summary at the end – I am not looking for that. I am looking for a way to correlate the real-time consumption during specific program blocks of my application. A profiler like collect/gprof that can tell me things like this

  • that this area is where most context switches are happening due to waits
  • specific functions where NFS access is happening.

Since my system is dedicated, I am not worried about other processes that might impact these profiles.

Get this bounty!!!

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