Linux: How to measure memory usage for a thread within process?

Question

I want to measure memory usage for each thread within process. Is it possible? I'm trying to figure out which thread leaks memory.

Edit 1. The pmap for leaking process shows ~600 allocation by [ anon ]

...
63b00000    772K rw---    [ anon ]
63bc1000    252K -----    [ anon ]
63c00000    772K rw---    [ anon ]
63cc1000    252K -----    [ anon ]
63d00000    772K rw---    [ anon ]
...

Advice on what to do next?

Edit 2. Only virtual memory is leaking e.g. physical memory usage is stable.

Answer 1

No this isn't possible, because memory isn't attached to a thread but to the process. There is no link between a thread and some part of the memory.

What you seem to need is a profiler, which would point to the allocation points. One of them (didn't use it in the last decade) is Rational Purify.

Answer 2

You generally can't identify the memory usage of a thread because memory ownership can freely move between threads. The kernel mapping tables will show you the usage of the process as a whole, i.e. the memory allocated for all threads.

Thread programming is hard. Unless you really need to freely share pointers and memory between threads - which is a fairly nasty code smell - it will probably be easier to debug if you rework your program as a flock of processes that communicate over IPC, which will also force you to consider which state needs to be shared. As a bonus, if the leaky process turns out to be a relatively short-lived one, the memory is returned to the system on exit() without you having to locate and patch the leak.