cmd/pprof: Ability to attribute memory usage to different instances of structs

[aditighag]

I believe the pprof tooling can provide more information to help debug certain memory leak issues. Here is a (simplified) pseudo code to explain what additional information I'm looking for -

type Foo struct {
   c Cache 
}
type Bar struct {
   c Cache
}
s1 Foo
s2 Bar

type (c *Cache) Populate { -----> results in memory leak for s1 but not s2
   
}

Go tool proof (invoked with either inuse_space or inuse_objects would show that memory usage is increasing in the type (c *Cache) Populate, but it would be helpful if the tooling could attribute the memory usage to the different instances - s1 vs s2? While you can argue different design based the pseudo code, the feature request is relevant more generally.

Edit : I think this falls under the "feature request" category, but I'm unable to update the labels.

[rsc]

The tooling does not really work that way. It is attributing allocations to functions that call the allocation routines. It has no idea where that memory goes or what it is held by. I don't see a way to do what you are asking for. A heap dump would show information like that, but we don't have particularly great support for that at the moment.

[aditighag]

A heap dump would show information like that

Can you elaborate on how one could go about getting the information from heap dumps?

[ianlancetaylor]

A good heap dump will let you trace from a global variable like s1 or s2 to all the memory to which those variables point.

[ianlancetaylor]

I don't see a path forward here, so closing. Please comment if you disagree.