Re: [gentoo-user] Re: Best way to improve interactivity with heavy disk activity?

[Stroller]

On 29/11/2010, at 1:18am, Nikos Chantziaras wrote:
> ...
> Also try to set these in your make.conf:
>
> PORTAGE_NICENESS=19
> PORTAGE_IONICE_COMMAND="sh -c \"schedtool -D \${PID}; ionice -c 3 -p \${PID}\""
>
> This will run all emerges nice 19, "idle" i/o priority and SCHED_IDLEPRIO CPU scheduling.  The "ionice" and "schedtool" utilities must be installed of course.
>
> I think you will love the results ;-)  Given enough RAM, emerging packages will have almost no effect on the system's usability.  In my case, I can for example watch 1080p HD movies without problems while building OpenOffice.

I don't think I've ever had much problem with emerges.

These DVD rips cause *much* slower responsiveness than I've ever noticed before.

The DVD drive is on the motherboard's EIDE controller, the hard-drive is part of a RAID5 on a 3ware PCI hardware SATA RAID controller. 

I'm aware that PCI is a relatively slow interface for modern hard-drives, but its adequate for everything else. 

When I have a DVD rip running it'll take 30 seconds to run `man man` or even exit bash - if I type `exit` in a tmux window then that window will stay around for 30 seconds.

Mark Knecht's suggestion that this is related to RAM usage seems quite credible, as it seems to be worse when I come back to the machine (say after 15 minutes after initiating the rip) and seems to be alleviated somewhat after I've run a few commands (`ls` on my home directory or other common places).

Checking now it seems pretty snappy - it's now on the `mkisofs` part of the rip, rather than the `dvdbackup` part. So it might be that the problem is only when the DVD-rom is reading at the same time as writing to the SATA controller.

Note that these are only "rips", NOT transcodes of the video. I am only running `dvdbackup && mkisofs`, so there should be minimal CPU overhead (although I'll now remember to double-check that tomorrow).

Stroller.