FAA Porteus acting too swappy/sleepy: (Cache?) Tunables?
Posted: 24 Mar 2015, 21:49
Hi,
I'm running Porteus 3.1 with 4GB ram, 1GB devoted to win7u in Vbox, and an encrypted changes.dat file.
Often the system acts like it's swapping itself to death. Especially when switching between the VM and the KDE desktop, but often enough within one or the other when both are running (ie: problem will crop up at the desktop when Vbox is busy in the background or even mostly idle, and crop up in the Vbox even when the Porteus host is mostly idle), and apparent even when VBox isn't running ie: when I have too many tabs open in Firefox on KDE.
Oh: the symptom is long delays (10's of seconds) before mouse actions, closing windows, changing focus etc. are recognized and responded to (ie: redraws). Likewise display (both in VBox and KDE) sometimes freezes for long periods, ie: no performance meter updates.
This seems to happen regardless as to whether or not I have a small zram set-aside for swap, and regardless as to whether or not the zram swap is being used as reported by "free -m." Though I haven't done any benching or objective comparisons.
I'm doubly puzzled as to how the system can act like it's swapping even when there is no swap, but I can imagine what's going on:
I'm wondering if there's just too much or too little caching of one kind or another. I'm thinking important pages are being tossed to make room for disk buffers and read-ahead stuff of dubious value. In some cases I'm confused as to where data is being cached to and from, wondering if some programs manage caches of their own outside of the normal Linux/FS caches: ie: is Firefox and maybe even KDE maintaining caches of their own in on-disk files? I've got Firefox caching turned off in prefs, but that's not really the kind of caching I mean: more like caching display objects ie: tabs in Firefox, windows/contents in KDE.
I tend to remember there are some tunable parameters which might help, ie: which favor code pages over user data or something like that. But I forget what these parameters are and where they are set (was a BSD whiz 25 years ago, when just about everything was in rc.local: not up to speed on Linux/Porteus boot sequence).
What should I be looking for, and in what files should I modify my options?
Curious as to the limits of tuneability here, can I favor "out of memory" messages, particularly for user processes, over aggressive cache cleanup? That is, favor response time of previously open tabs in Firefox and disfavoring or flat out preventing the opening of new tabs until I've closed some old ones (bad habit).
Could even good ole' ulimit and/or sysctl be leveraged to help?
Thank you in advance for any assistance, I'll report back with any progress.
I think I'll try running from RAM, with EXIT in the changes cheatcode, etc. a bit more to see what impact that has.
-jeff
I'm running Porteus 3.1 with 4GB ram, 1GB devoted to win7u in Vbox, and an encrypted changes.dat file.
Often the system acts like it's swapping itself to death. Especially when switching between the VM and the KDE desktop, but often enough within one or the other when both are running (ie: problem will crop up at the desktop when Vbox is busy in the background or even mostly idle, and crop up in the Vbox even when the Porteus host is mostly idle), and apparent even when VBox isn't running ie: when I have too many tabs open in Firefox on KDE.
Oh: the symptom is long delays (10's of seconds) before mouse actions, closing windows, changing focus etc. are recognized and responded to (ie: redraws). Likewise display (both in VBox and KDE) sometimes freezes for long periods, ie: no performance meter updates.
This seems to happen regardless as to whether or not I have a small zram set-aside for swap, and regardless as to whether or not the zram swap is being used as reported by "free -m." Though I haven't done any benching or objective comparisons.
I'm doubly puzzled as to how the system can act like it's swapping even when there is no swap, but I can imagine what's going on:
I'm wondering if there's just too much or too little caching of one kind or another. I'm thinking important pages are being tossed to make room for disk buffers and read-ahead stuff of dubious value. In some cases I'm confused as to where data is being cached to and from, wondering if some programs manage caches of their own outside of the normal Linux/FS caches: ie: is Firefox and maybe even KDE maintaining caches of their own in on-disk files? I've got Firefox caching turned off in prefs, but that's not really the kind of caching I mean: more like caching display objects ie: tabs in Firefox, windows/contents in KDE.
I tend to remember there are some tunable parameters which might help, ie: which favor code pages over user data or something like that. But I forget what these parameters are and where they are set (was a BSD whiz 25 years ago, when just about everything was in rc.local: not up to speed on Linux/Porteus boot sequence).
What should I be looking for, and in what files should I modify my options?
Curious as to the limits of tuneability here, can I favor "out of memory" messages, particularly for user processes, over aggressive cache cleanup? That is, favor response time of previously open tabs in Firefox and disfavoring or flat out preventing the opening of new tabs until I've closed some old ones (bad habit).
Could even good ole' ulimit and/or sysctl be leveraged to help?
Thank you in advance for any assistance, I'll report back with any progress.
I think I'll try running from RAM, with EXIT in the changes cheatcode, etc. a bit more to see what impact that has.
-jeff