Re: [PATCH pve-qemu 0/2] Re-enable tcmalloc as the memory allocator

Fiona Ebner
2026-04-13T08:14:50Z

Am 10.04.26 um 12:44 PM schrieb DERUMIER, Alexandre:
>
>>> How does the performance change when doing IO within a QEMU guest?
>>>
>>> How does this affect the performance for other storage types, like
>>> ZFS,
>>> qcow2 on top of directory-based storages, qcow2 on top of LVM, LVM-
>>> thin,
>>> etc. and other workloads like saving VM state during snapshot,
>>> transfer
>>> during migration, maybe memory hotplug/ballooning, network
>>> performance
>>> for vNICs?
>
> Hi Fiona,
>
> I'm stil running in production (I have keeped tcmalloc after the
> removal some year ago from the pve build), and I didn't notice problem.
> (but I still don't use pbs).
>
> But I never have done bench with/without it since 5/6 year.
>
> Maybe vm memory should be checked too, I'm thinking about RSS memory
> with balloon free_page_reporting, to see if it's correcting freeing
> memory.

Thanks! If it was running fine for you for this long, that is a very
good data point :) Still, testing different scenarios/configurations
would be nice to rule out that there is a (performance) regression
somewhere else.