Finding the Location of Logs with --log-function-events on Chrome OS

[Tyler Gross]

I'm trying to benchmark parsing times on Chrome OS. I've done all that's necessary to enter developer mode and all that to run Chrome with flags and I can verify the flags in chrome://version.

The issue is that I can't actually find where the function logs are stored. On MacOS, when you run Chrome with --no-sandbox --js-flags="--log-function-events" the logs are just placed in the same directory as the application binary itself, but I can't seem to find where that is in Chrome OS. I also had an issue where I had to run Chrome on MacOS with sudo to get logs or move it to a non-root directory, which I wonder if that's the same issue on ChromeOS.

Much appreciated if anyone can help out here!

[david....@gmail.com]

Since you are in developer mode, you will need to enter the shell command at the crosh prompt. All the logs are in /var/log and the folders therein.

[david....@gmail.com]

And no need for sudo. 

lots of normal Linux utilities are available including grep

[Tyler Gross]

I looked in the /var/log folder, but I wasn't able to find any logs that were isolate.log files. Is there something else that I'm missing that allows Chrome's renderer process to write to disk on Chrome OS?

[DennisLfromGA]

Even in normal verified boot mode (without dev mode) you can view the logs in a new tab at: file:///var/log/

[Tyler Gross]

I think the files must not be being written or something like that cause even using the file browser like you said in Chrome, I don't see any isolate log files.

[david.stavert]

There are other .log files outside of /var/log You could try
sudo find / -name isolate.log

[Tyler Gross]

I tried this once before, but it just seemed like it was taking forever and never yielded any results, but I'll try again.

[david.stavert]

It can take a while. Let continue until you get the command prompt again
If it comes back without finding the log file name you are looking
for, try find / -name *.log >~/Downloads/logfiles.txt and then look
through the logfiles.txt files and see if any other interesting
logfile shows up

On Tuesday, Aug 16, 2022, 9:48 AM, wrote:

> I tried this once before, but it just seemed like it was taking forever and
> never yielded any results, but I'll try again.
>
> On Tuesday, August 16, 2022 at 10:44:44 AM UTC-4 david....@gmail.com wrote:
>

> > There are other .log files outside of /var/log You could try
> > sudo find / -name isolate.log
> >
> >

[DennisLfromGA]

Tyler...

Are you sure there is such a file in ChromeOS?

I just ran this and came up empty: find / -type f -name '*isolate*.log' -ls 2>/dev/null

[Tyler Gross]

There isn't such a file just by default. Once you enable the --log-function-events flag, then the renderer process will start dumping these function event logs that are named something like isolate-0x11800b90000-36041-v8.log on MacOS.

I've attached an example of one of these files below.

[DennisLfromGA]

Oh, sorry, Tyler... I totally overlooked that requirement.

[Tyler Gross]

I just tried doing this on Linux as well to no avail. It seems like the sandbox is properly disabled as well if I go to chrome://sandbox, but I still don't see the isolate files being written anywhere.