Re: Virtual Threads

Dear Annick,
     a CST process that runs a block that does as little as possible (so 
context stacks stay as short as possible) will create 3-4 contexts that 
can be allocated virtually in the stack zone. If they are all reified 
then (on a 64 bit system), that is less than 1Kb.  If the process needs 
a name, or per-process variables, or actually does something that 
requires a stack, the memory requirement grows, with stack depth and 
object allocation within a context being the main drivers.  I offer a 
guess of 5kb for a more realistic process than the 1Kb minimum (and it 
would be more if it were running THAPI calls).

Stack space for an actively-running process comes from the stack zone, 
shared between all processes (can be reallocated at boot time).  A 
process with a stack too deep to fit in the stack zone (or one that is 
relatively inactive) gets swapped out of the stack zone into context 
objects (limited only by how much object memory you can allocate).

                     HTH
                         Niall Ross


On 02/03/2022 08:47, Annick wrote:
> Hi,
>
> 	I was attending yesterday a talk on the Java Loom project, which aims at implementing virtual threads (instead of OS threads) in Java.
> 	In particular I learned that any Java thread allocates 2M in memory, which limits considerably the physical number of threads in a server.
> 	Does anyone know the comparison between Smalltalk processes and Java virtual threads ?
>
> 	
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