Feature request: seqential mode for hdd

[axet]

gdu scanning folders in parallel, which is good for SSD, but can slow down scan progress for HDD. Can gdu detect device type (by reading /sys/block/nvme0n1/queue/rotational of current FS) or has a '-s|--sequential' flag?

[dundee]

You can use the --max-cores or -m option and set it to 1.

[axet]

I tried. It keep scanning in random order.

[dundee]

Please try the option and feel free to reopen this if you think it's not working correctly.

[axet]

Here is no "reopen" issue option for me. I like first version of github much better then current one.

About the issue. I did test '-m 1' option before opening the issue. And test it again, same results:

When drive scanning, current folder jumping from one folder to original folder and back and forth. Like that:

/media/admin/1TB/Games...
/media/admin/1TB/Soft...
/media/admin/1TB/Games...

etc... It looks like it does it in random order, which can cause slowdown, since folder reading is not done in sequential order.

gdu 5.22.0-1+b1

[dundee]

If you need strictly sequential scanning, isn't ncdu better for you use case then?

[axet]

Do you actually had in mind that gdu would be SSD only project? If so, then you are right. ncdu is where I should go.

But, since I'm missing background deletion in booth projects ncdu and gdu first project implementing this would be a project I want to stay with... It is much easier to implement multithreading / background tasks in go. And I assume this project would implement it first. (I tried to make it work for ncdu but code base is too hard to manage).

I do not like idea to make / keep this project as SSD only.

[dundee]

Yes, I plan to implement background deletion soon (this month hopefully). In that case it makes sense to improve Gdu to work better on HDDs as well.

[axet]

Thanks! Here is a field report:

axet@axet-desktop:/media/axet/1TB$ sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'
axet@axet-desktop:/media/axet/1TB$ time gdu

real	23m34,345s
user	1m50,510s
sys	1m48,378s
axet@axet-desktop:/media/axet/1TB$ sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'
axet@axet-desktop:/media/axet/1TB$ time gdu -m 1

real	15m46,976s
user	1m7,590s
sys	1m21,093s
axet@axet-desktop:/media/axet/1TB$ sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'
axet@axet-desktop:/media/axet/1TB$ time gdu --sequential

real	8m34,558s
user	0m43,872s
sys	1m6,693s

I suggest to add automatic detection of underlying device using /sys files:

cat /sys/devices/virtual/block/zram0/queue/rotational

1 - for hdd
0 - for ssd

additional option maybe required for manual mode: --parallel