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Hjdskes / powersave

Linux power save settings, compatible with systemd
Do What The F*ck You Want To Public License
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What is the use of sysctl.d/99-powersave.conf for an SSD drive? #4

Open adrfantini opened 7 years ago

adrfantini commented 7 years ago

Most of the content of sysctl.d/99-powersave.conf refer to delaying disk writes, which should be, if I'm not mistaken, not necessary on an SSD drive. Is this wrong? Did you do any testing?

Thanks

Hjdskes commented 7 years ago

That depends on what you mean with "not necessary", I suppose. If your goal is power saving, then you are probably correct in that it does not save as much power on an SSD as it does on an HDD (haven't tested how much of a difference, if any, it makes. I assume it would be negligible). However, less writing improves the lifespan of your SSD so in that sense you could deem it necessary (although, with modern SSDs, this is also not much of an issue anymore).

In any case, it won't hurt to have them listed. Most of the entries in that file are currently commented, too.

adrfantini commented 7 years ago

Still it wouldn't be bad to specify that the powersaving impact of those changes are probably minimal for SSDs. I would think that with a modern SSD those settings are probably best left at the default values as the benefits are very limited, and you pay a small price in responsiveness and amount of data lost on a crash.

Thanks for the good job, by the way. Your tweaks are very comprehensive and useful.

2017-01-27 11:50 GMT+01:00 Jente Hidskes notifications@github.com:

That depends on what you mean with "not necessary", I suppose. If your goal is power saving, then you are probably correct in that it does not save as much power on an SSD as it does on an HDD (haven't tested how much of a difference, if any, it makes. I assume it would be negligible). However, less writing improves the lifespan of your SSD so in that sense you could deem it necessary (although, with modern SSDs, this is also not much of an issue anymore).

In any case, it won't hurt to have them listed. Most of the entries in that file are currently commented, too.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/Hjdskes/powersave/issues/4#issuecomment-275638864, or mute the thread https://github.com/notifications/unsubscribe-auth/AMO2HQzVh_xLdic1S-9uqmmUJebR2Bekks5rWcvjgaJpZM4Lvjp0 .

Hjdskes commented 7 years ago

Still it wouldn't be bad to specify that the powersaving impact of those changes are probably minimal for SSDs.

I'm planning on writing an in-depth blog post about these settings, in which I will definitely mention this. I'll add it to the README too.

I would think that with a modern SSD those settings are probably best left at the default values as the benefits are very limited, and you pay a small price in responsiveness and amount of data lost on a crash.

They are left at the defaults, except for vm.dirty_writeback_centisecs (which, I admit, is a leftover from the time where I did not have an SSD - I'll probably change it when I write that blog post). In this case I'd still like to keep them in, if only to notify others of their existence. I have not noticed a (however small) decrease in responsiveness nor (increased) data loss on a system crash. In any case, feel free to change the settings to whatever you prefer!

adrfantini commented 7 years ago

Yeah, of course. Just wanted to make sure that it was clear that on SSDs the settings do not change much.

All the best, thanks!

2017-01-28 15:44 GMT+01:00 Jente Hidskes notifications@github.com:

Still it wouldn't be bad to specify that the powersaving impact of those changes are probably minimal for SSDs.

I'm planning on writing an in-depth blog post about these settings, in which I will definitely mention this. I'll add it to the README too.

I would think that with a modern SSD those settings are probably best left at the default values as the benefits are very limited, and you pay a small price in responsiveness and amount of data lost on a crash.

They are left at the defaults, except for vm.dirty_writeback_centisecs (which, I admit, is a leftover from the time where I did not have an SSD - I'll probably change it when I write that blog post). In this case I'd still like to keep them in, if only to notify others of their existence. I have not noticed a (however small) decrease in responsiveness nor (increased) data loss on a system crash. In any case, feel free to change the settings to whatever you prefer!

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/Hjdskes/powersave/issues/4#issuecomment-275852013, or mute the thread https://github.com/notifications/unsubscribe-auth/AMO2HbvQlMrE-ahAvIo51dajztuqDV5Oks5rW1Q8gaJpZM4Lvjp0 .

Hjdskes commented 7 years ago

No problem, I appreciate the message!