Re: [HTCondor-users] zswap for jobs

[Emily Kooistra <a66@xxxxxxxxx>]

Hi Bert,

Thanks for the info!

On 4/8/26 12:36, Bert DeKnuydt wrote:
> > Does anyone have operational experience with running zswap on EPs?
>
> Yes. I've been running zswap for years, on almost everything, including 
> EPs. Here, most jobs use little or no
> swap at all, but some just 'explode', often only temporarily. I've 
> always had the (admittedly: subjective) feeling
> that EPs tend to survive such events (as in remaining responsive) much 
> better using zswap. In fact, I see little
> disadvantage in enabling it (as compared to zram).
Thats good to hear.
> > I was wondering what the compression rates people are getting for this?
>
> No hard numbers; I doubt for real data it's more than 2.
That was also my expectation.
> In my opinion, that's the advantage of zswap: the kernel manages the 
> lot, there's no tuning needed (balancing between
> zwap and disk-cache).
Yea that was also my impression, altho beeing able to limit the total 
amount of memory a job can store in zswap would be beneficial, given 
this right now is unlimited. (Or well up to the system max), by having 
condor also set memory.zswap.max based on a classadd expresion, similary 
to the other cgroup limits.

Emily