Null
Snug
You may find the following video helpful.
Torvalds Warns the World: Don't Use the Linux 5.12-rc1 Kernel
- Thread starter Linux-SWAT
- Start date
sebt3
homebrew player (P. & C.)
The f**k ?
Swap is evil, why dedicating a f**king drive to it ? as fast as a SSD drive can be, it's still 100 times slower than RAM. You dont have enough RAM on your machine ? buy more of it not a drive 100 times slower.
Modern architecture like kubernetes mandate NO swap (kubelet wont start otherwise...), there's a good point behind this.
I have 4gb Ram on my Pyra, why would i need a Swapfile? But on the other side: Its the successor of a device who works quite good whit only 256 mb Ram..
Null
Snug
I found it an explosive revelation too.
levi
Still fresh, damnit!
All of the machines I own have had their ram maxxed out long ago. As I say I don't use swap as most of the processes I run simply limit themselves to the available RAM and CPU time. I think the most common need to for ram than you have is games and things that procedurally generate massive textures and maps but store those in RAM at startup to speed up access.
No need for a Terminal Use on the Pyra: there is also the Mate Diagnostic Software for this purpose
elw3
ƐʍlƎ
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Quite the opposite.
Firstoff modern SSDs outperform rams from like 15 years ago, DDR2 speeds are possible.
Second Ram speeds dont really affect most programs. What needs to be fast has plenty of space in the cpu cache these days. After all that cache is the primary reason a computer is fast at all.
I rather question if ram is needed at all anymore. Why waste money for it when 20 bucks can get you something way bigger and less power using?
Now dont give me an "but but but" speech, i know it works cause this is how my computer runs right now: 4gb of throttled ddr3 that runs at 1/4 of its rated speed to save energy and an old 30gb ssd dedicated for swap.
These only kick in for bigger programs, darktable, gimp and audacity to be precise. They run totally snappy, cpu speed is the bottleneck in every operation, thus i consider it maxed out.
Now if your modern architecture has problems with it i suggest using less crappy software instead.
hns
Well-Known Member
You wouldn't have noticed either. The bug is only about configuring a swapfile which is usually not used on SD cards (too much wear) and only needed if you are doing RAM intensive work when the internal RAM (512 MB / 4 GB) is not enough.
And we already have -rc2 for Pyra and Pandora: https://lists.goldelico.com/pipermail/letux-kernel/2021-March/006490.html
ED and the PyraOS developers do not use -rc versions but distribute older and mature kernels.
sebt3
homebrew player (P. & C.)
There's not a single way an SSD can be faster than RAM.
The CPU have a direct connection to the RAM (well with multi socket systems it's a little more complicated, but lets forget this for a bit). An M.2 drive is piloted by the CPU throw interrupts, these interrupts go throw the south-bridge to enter the PCI-e line then get to the M.2 controller that indirect the call to the actual drive. The buffer follow the road back to the main data line where it enter ... the fucking RAM...
How the fuck all these indirections that finally endups in the RAM can be faster than the RAM itself ? Could you explain me this ?
Do you know how the linux kernel work ? Any write to a disk is cached into RAM so the write is faster for the program, the kernel making sure the data is written to disk in an async fashion. (yeah async write is the default. Getting sync write is actually cumbersome and a bit convulted).
Removing RAM from a computer would requiere a completly new hardware design and a completly new OS design. While the linux kernel is the most versatile kernel ever written, it would need a complet redesign for your idea to works. A redisign that would make the 1.x->2.0 and the 2.2->2.4 redisigns as mer simple patches...
BTW, I was talking about software architecture used in datacenter. kubernetes is pretty much this. Google, amazon and a few others are running using kubernetes, thuss without any swap... I guess you think you understand better hardware than the google engineers that designed kubernetes and the hardware it's running on top of...
seb already said it, but:
i believe you do not fully understand of how your system is behaving
specifically: 100 megapixel images can fit easily in 4G of ram
i don't believe you are relying heavily on swap at all
so you don't notice it's poor performance
why do i care?
i'd like to see swap disabled by default on the pyra
if there are arguments in favor of swap, i'd like them to be sound
Post automatically merged:
i'll add: it's the most sophisticated (and successful) software mankind has ever seen
levi
Still fresh, damnit!
It's even true if you look simply at the bandwidths. As I read it, old DDR2-400 RAM has a bandwidth of 3200MB/s, while modern SATA has a rated bandwidth of up to 6Gb/s, which is 750MB/s. With raditional spinning iron oxide based media, the seek time part of latency will be significant, but an entirely electronic disc should not have the same limitation. But still, a DDR2 board directly wired to a fast memory bus will run at 3200MB/s all of the time, whereas a SATA disc is presumably connected over the northbridge, and perhaps shares bandwidth with PCI cards, and only tops out at 750MB/s.
Linux-SWAT
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I see swap as both a safeguard and a warning when used.
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