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gta198
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swappiness?

If you are using a solid state drive, is it advantageous to change your "swappiness" setting?
Does it help a platter drive to change it?
I've seen a lot of arguments for it and some that claim it doesn't really change anything. None of them said anything about crunching so I thought I would ask here.
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Former Member
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Re: swappiness?

When using Ubuntu for years, long dumped, I used swappiness at 60 if I recollect correctly like sudo sysctl vm.swappiness=60. Whatever it did, disk was never touched, swap ran completely in memory, but think that's anyway a feature of Linux.

Edit: More benefit for changing the Write to disk at most. The machine was running 24/7 so why the heck allow checkpoints to be written default at most every 60 seconds. Set it to 600, 1200, 1800, 3600 seconds. If you run 8-12-16 and more threads concurrent that's a bunch less writing.
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[Edit 2 times, last edit by Former Member at May 25, 2020 7:42:14 AM]
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floyd
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Re: swappiness?

When using Ubuntu for years, long dumped, I used swappiness at 60 if I recollect correctly like sudo sysctl vm.swappiness=60. Whatever it did, disk was never touched
I'm using Debian with default settings. There's always a few megabytes swapped out, even where enough RAM is available, but I don't see a problem with that.

The machine was running 24/7 so why the heck allow checkpoints to be written default at most every 60 seconds. Set it to 600, 1200, 1800, 3600 seconds.
I like frequent checkpoints. I'm running 24/7 too but sometimes you have to reboot. That always takes hours of preparation if you run many threads which rarely checkpoint.

If you run 8-12-16 and more threads concurrent that's a bunch less writing.
Oh yes, some projects write huge amounts of data. OPN and ARP come to mind, and reducing the checkpoint frequency doesn't help much with the latter. I'm moving my data directories away from SSD wherever possible.
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Former Member
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Re: swappiness?

Boot? If at all, once a month. With Linux, really never, and then planned, which means setting to stop the running tasks after next checkpoint. That can be fully automated with BOINCTasks.
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hchc
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Re: swappiness?

I have a couple dedicated crunchers on Debian Linux that both run off USB flash drive. On installation, I've completely not created a swap partition at all to basically force the machine to not swap to disk. (Must of course ensure you have enough RAM. The dual-core machine has 4 GB of RAM, and the quad-core machine has 8 GB of RAM.)

Additionally, in BOINC/Computing preferences:
  • Under "Disk and memory," I have "Page/swap file use at most" set to 1%. It doesn't allow 0% unfortunately.
  • "Leave non-GPU tasks in memory when suspended" is checked.
  • "Request tasks to checkpoint at most every" is set to 1800 seconds (30 minutes).

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  • i5-7500 (Kaby Lake, 4C/4T) @ 3.4 GHz
  • i5-4590 (Haswell, 4C/4T) @ 3.3 GHz
  • i5-3570 (Broadwell, 4C/4T) @ 3.4 GHz

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[Edit 2 times, last edit by hchc at May 25, 2020 7:48:08 PM]
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floyd
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Re: swappiness?

Boot?
Sure. I can think of various reasons why I'd want to reboot even if it's not strictly necessary in all cases. If it's necessary, advisable or only the fastest or safest solution I don't hesitate to reboot and I want to be able to do it now and go on, not put it on a to do list. I run my own personal computers, I'm not obliged to keep them up for as long as possible and I don't need to feel like a professional administrator.

If at all, once a month.

planned, which means setting to stop the running tasks after next checkpoint

Once a month is annoying enough if you can't automate the preparation.

That can be fully automated with BOINCTasks.
No Windows here and I don't install wine just for one option of a single program.
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Former Member
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Re: swappiness?

BOINCTasks works on both Windows and Linux/Ubuntu. It's a multi-client manager at that, 1 view with all the running hosts on a LAN in one view, it's even internet remote monitoring enabled in a browser based. You said you were concerned about loosing time with long checkpoint intervals, gave a solution. And greatly reduce disk writing, which seemed to fit gta's topic. Knowledge shared for everyone who can benefit from it, to benefit from it.
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[Edit 1 times, last edit by Former Member at May 26, 2020 8:52:24 AM]
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Aurum
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Re: swappiness?

Additionally, in BOINC/Computing preferences:
Under "Disk and memory," I have "Page/swap file use at most" set to 1%. It doesn't allow 0% unfortunately.

That sounds risky to me. Projects like Rosetta, LHC ATLAS, ARP, etc use a lot of RAM and they may need to use swap. I set all mine to 95% with a swap of 16 GB:
sudo swapoff -a
sudo dd if=/dev/zero of=/swapfile bs=1M count=16384
sudo mkswap /swapfile
sudo swapon /swapfile

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...KRI please cancel all shadow-banning
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floyd
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Re: swappiness?

BOINCTasks works on both Windows and Linux/Ubuntu.
This is the first time I hear of a native Linux version. I'll try it, thanks.
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Former Member
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Re: swappiness?

It runs in an emulation frame if IIRC, some prerequisites, not 'native', but it worked great nonetheless. I just used a Windows machine to monitor all on the LAN, even configured it to handle the dual boot device, i.e. 2 entries in the BOINCTasks computer list. There's a web based monitor version too allowing control through tablet and phone (efmer's words).
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[Edit 1 times, last edit by Former Member at May 28, 2020 9:42:39 AM]
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