Caching gdb target data to speed up builing in Vscode / Torizon

Technical Support
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1

Dear all,

I would like to speed up the launch of gdb when developping under VSCode / Torizon.

Loading symbols takes a lot of time, while these are always the same. For instance, the Debug Console shows hundreds of lines like this :

...
Reading /usr/lib/aarch64-linux-gnu/292df03e86d8c16a47592b4aca39d4e673f56d.debug from remote target...
Reading /usr/lib/aarch64-linux-gnu/.debug/292df03e86d8c16a47592b4aca39d4e673f56d.debug from remote target...
Reading /usr/lib/debug//usr/lib/aarch64-linux-gnu/292df03e86d8c16a47592b4aca39d4e673f56d.debug from remote target...
Reading /usr/lib/debug/usr/lib/aarch64-linux-gnu//292df03e86d8c16a47592b4aca39d4e673f56d.debug from remote target...
Reading target:/usr/lib/debug/usr/lib/aarch64-linux-gnu//292df03e86d8c16a47592b4aca39d4e673f56d.debug from remote target...
...

I tried to add a section in .vscode/launch.json to enable caching as follows, but it does not help

"setupCommands": [
                {
                    "description": "Setting architecture",
                    "text": "set architecture %{torizon.gdb-arch}",
                    "ignoreFailures": false
                },
                {
                    "description": "Setting cache on",
                    "text": "set index-cache on",
                    "ignoreFailures": false
                }

Any other idea how to speed up gdb execution ?

Best regards,
Fabian

2

Hello @fdortu
I think that the correct syntax is:

set index-cache enabled on

Can you try with that and see if it works?

Best regards,
Josep

3

Yes I already tried with enabled as it is referenced in the manual, but then I get an error message from gdb saying the command does not exist.

4

Hi @fdortu !

Sorry for the delay. I asked internally if someone could help with this.

I will get back to you as soon as I have more information.

Best regards,

5

Hello @fdortu,

You are right. Loading the symbols from the target to the host over the network causes a delay in building your program. What you could do as a workaround is to copy those shared libs from your target to a location in your host and set solib-absolute-prefix and solib-search-path to that location. This way, you don’t retrieve them through the network every time you start the session. In my setup, I copied the /lib/ld-linux-aarch64.so file from my target to /tmp/host/lib/ on my host machine and modified the launch.json file accordingly:

"setupCommands": [
                {
                    "description": "Setting architecture",
                    "text": "set architecture %{torizon.gdb-arch}",
                    "ignoreFailures": false
                },
                {
                    "description": "Setting local path for target's shared object",
                    "text": "set solib-absolute-prefix /tmp/host",
                    "ignoreFailures": false
                },
                {
                    "description": "Setting search path for target's shared object",
                    "text": "set solib-search-path /tmp/host/lib",
                    "ignoreFailures": false
                }
]

That solved this issue for me. Please let me know if that works for you. Happy coding :slight_smile:

Best regards,
Rudhi

6

Great it works !

Actually, specifying set solib-absolute-prefix /tmp/host is enough as long as the directory structure within /tmp/host respects the one on the host.

Btw, comas are missing between the brackets }{ → },{

In summary, the following works for me

"setupCommands": [
                {
                    "description": "Setting architecture",
                    "text": "set architecture %{torizon.gdb-arch}",
                    "ignoreFailures": false
                },
                {
                    "description": "Setting local path for target's shared object",
                    "text": "set solib-absolute-prefix ${workspaceRoot}/cache-host",
                    "ignoreFailures": false
                }
            ]
7

Hi @fdortu,

I’m glad that it works for you. Also, thanks for pointing out the mistake. I have edited the solution by adding the comas so that it will be helpful to someone else later :slight_smile:

Best regards,
Rudhi