On Thu, Jun 8, 2023 at 11:54 AM Hannu Krosing <[email protected]> wrote: > > On Wed, Jun 7, 2023 at 11:37 PM Andres Freund <[email protected]> wrote: > > > > Hi, > > > > On 2023-06-05 13:40:13 -0400, Jonathan S. Katz wrote: > > > 2. While I wouldn't want to necessarily discourage a moonshot effort, I > > > would ask if developer time could be better spent on tackling some of the > > > other problems around vertical scalability? Per some PGCon discussions, > > > there's still room for improvement in how PostgreSQL can best utilize > > > resources available very large "commodity" machines (a 448-core / 24TB RAM > > > instance comes to mind). > > > > I think we're starting to hit quite a few limits related to the process > > model, > > particularly on bigger machines. The overhead of cross-process context > > switches is inherently higher than switching between threads in the same > > process - and my suspicion is that that overhead will continue to > > increase. Once you have a significant number of connections we end up > > spending > > a *lot* of time in TLB misses, and that's inherent to the process model, > > because you can't share the TLB across processes. > > > This part was touched in the "AMA with a Linux Kernale Hacker" > Unconference session where he mentioned that the had proposed a > 'mshare' syscall for this.
Also, the *static* huge pages already let you solve this problem now by sharing the page tables Cheers Hannu
