Fix heapsize hint and use a line for max memory #48747
Conversation
so that large machines utilize more of their ram
|
Is the equation correct? double percent = ngigs * 0.00703125 + 0.6; // 60% at 0 gigs and 90% at 128 toFor |
|
Oops, It's not correct at all :). Thanks |
expose the max heap size to Sys
|
Couldn't this lead us to OOM more frequently on large shared machines? |
|
You have more gigabytes to spare on a large machine than a small so I dont think that would be the case. |
A64FX has 32 GiB of memory for 48/50 cores |
|
I'm not sure there's a clean solution for something like that. Outside of using heap-size hint. |
Could you spell out the implications of this in this context for me? |
My understanding of your comment was that you wanted to suggest "large machines" have large memory, was that not the case? |
|
Our reasoning of large machine here is lots of total memory. Not cores specifically |
|
I meant, for a machine with a lot of memory the "slack" that the GC gives is larger than that for a machine with little memory. For shared machines you should probably set up some cgroup containerization to share resources between users. |
src/gc.c
Outdated
| max_total_memory = total_mem / 10 * 6; | ||
| uint64_t ngigs = total_mem / 10e9; | ||
| if (ngigs < 128) | ||
| { |
There was a problem hiding this comment.
nit: align bracket with if condition
|
Minor comments. Overall makes sense to me. |
* Fix heapsize hint and use a line so that large machines utilize more of their ram (cherry picked from commit 51db8af)
The idea here is that there is a kinda fixed amount of background memory for OSs and other things, so on small machines we are more conservative, but if the user has a lot of ram we should try and use most of it.
Also fix heap-sizehint since it got broken on the last change.