Hi, sorry for bumping this old thread. I'm currently benching again qemu with librbd and memory allocator.
It's seem that they are still performance problem with default glibc allocator, around 20-25% less iops and bigger latency. From my bench, i'm around 60k iops vs 80-90k iops with 4k randread. Redhat have also notice it https://bugzilla.redhat.com/show_bug.cgi?id=1717414 https://sourceware.org/bugzilla/show_bug.cgi?id=28050 I known than jemalloc was buggy with rust lib && pbs block driver, but did you have evaluated tcmalloc ? Note that it's possible to load it dynamically with LD_PRELOAD, so maybe could we add an option in vm config to enable it ? Le mardi 15 décembre 2020 à 14:43 +0100, Thomas Lamprecht a écrit : > On 10.12.20 16:23, Stefan Reiter wrote: > > jemalloc does not play nice with our Rust library (proxmox-backup- > > qemu), > > specifically it never releases memory allocated from Rust to the > > OS. > > This leads to a problem with larger caches (e.g. for the PBS block > > driver). > > > > It appears to be related to this GitHub issue: > > https://github.com/jemalloc/jemalloc/issues/1398 > > > > The background_thread solution seems weirdly hacky, so let's > > disable > > jemalloc entirely for now. > > > > Signed-off-by: Stefan Reiter <s.rei...@proxmox.com> > > --- > > > > @Alexandre: you were the one to introduce jemalloc into our QEMU > > builds a long > > time ago - does it still provide a measurable benefit? If the > > performance loss > > would be too great in removing it, we could maybe figure out some > > workarounds as > > well. > > > > Its current behaviour does seem rather broken to me though... > > > > debian/rules | 1 - > > 1 file changed, 1 deletion(-) > > > > > > applied, thanks! > > > _______________________________________________ > pve-devel mailing list > pve-devel@lists.proxmox.com > https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel > _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
