Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

[SCOTT FIELDS via Gdb]

Are there other commands that will estimate the current space required for a successful run of "gcore"?

Neither "gcore" command or gcore/generate-core-file command in GDB provide any option to get such an estimate.

Has there been a request to get this kind of information from "gcore" as a future enhancement, since it can be difficult to know just how much space a large running process actually needs.

Scott Fields
Kyndryl
Senior Lead SRE - BNSF

Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

[SCOTT FIELDS via Gdb]

Are there other commands that will estimate the current space required for a successful run of "gcore"?

Neither "gcore" command or gcore/generate-core-file command in GDB provide any option to get such an estimate.

Has there been a request to get this kind of information from "gcore" as a future enhancement, since it can be difficult to know just how much space a large running process actually needs.

Scott Fields
Kyndryl
Senior Lead SRE

Re: Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

[Tom Tromey]

>>>>> SCOTT FIELDS via Gdb <gdb@sourceware.org> writes:

> Are there other commands that will estimate the current space required
> for a successful run of "gcore"?  Neither "gcore" command or
> gcore/generate-core-file command in GDB provide any option to get such
> an estimate.

> Has there been a request to get this kind of information from "gcore"
> as a future enhancement, since it can be difficult to know just how
> much space a large running process actually needs.

I've never heard such a request.

Looking at gcore.c, it seems reasonably possible to implement this.
Look at gcore_create_callback to see how it decides how to size the
various sections.  Without trying, it is hard to say if there is some
hidden gotcha.

Tom

Re: Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

[Luis Machado via Gdb]

On 9/8/23 17:56, Tom Tromey wrote:
>>>>>> SCOTT FIELDS via Gdb <gdb@sourceware.org> writes:
> 
>> Are there other commands that will estimate the current space required
>> for a successful run of "gcore"?  Neither "gcore" command or
>> gcore/generate-core-file command in GDB provide any option to get such
>> an estimate.
> 
>> Has there been a request to get this kind of information from "gcore"
>> as a future enhancement, since it can be difficult to know just how
>> much space a large running process actually needs.
> 
> I've never heard such a request.
> 
> Looking at gcore.c, it seems reasonably possible to implement this.
> Look at gcore_create_callback to see how it decides how to size the
> various sections.  Without trying, it is hard to say if there is some
> hidden gotcha.

I'd expect some help from the arch-specific code will be needed to add things like
memory tag data and sizes of register sets. But otherwise it should be fairly doable.

RE: Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

[SCOTT FIELDS via Gdb]

Where would I need to make a feature request for this?

-----Original Message-----
From: Tom Tromey <tom@tromey.com> 
Sent: Friday, September 8, 2023 11:56 AM
To: SCOTT FIELDS via Gdb <gdb@sourceware.org>
Cc: gdb@gnu.org; SCOTT FIELDS <Scott.Fields@kyndryl.com>
Subject: [EXTERNAL] Re: Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

>>>>> SCOTT FIELDS via Gdb <gdb@sourceware.org> writes:

> Are there other commands that will estimate the current space required 
> for a successful run of "gcore"?  Neither "gcore" command or 
> gcore/generate-core-file command in GDB provide any option to get such 
> an estimate.

> Has there been a request to get this kind of information from "gcore"
> as a future enhancement, since it can be difficult to know just how 
> much space a large running process actually needs.

I've never heard such a request.

Looking at gcore.c, it seems reasonably possible to implement this.
Look at gcore_create_callback to see how it decides how to size the various sections.  Without trying, it is hard to say if there is some hidden gotcha.

Tom

Re: Getting core estimate for "gcore" command and conversely gcore/generate-core-file in GDB

[Tom Tromey]

> Where would I need to make a feature request for this?

Well, you can file it in Bugzilla, but I should warn you that there
isn't really anybody who prowls Bugzilla looking for things to do.  That
is, if you want this, you're probably best off writing it yourself.

For it to go in, I suppose it would need some kind of rationale and/or
user interface.

thanks,
Tom