On Fri, 24 Nov 2023, David Hildenbrand wrote: > On 24.11.23 20:44, David Rientjes wrote: > > On Thu, 23 Nov 2023, David Hildenbrand wrote: > > > > > On 23.11.23 14:30, Gang Li wrote: > > > > From: Gang Li <ligang.bdlg@xxxxxxxxxxxxx> > > > > > > > > Inspired by these patches [1][2], this series aims to speed up the > > > > initialization of hugetlb during the boot process through > > > > parallelization. > > > > > > > > It is particularly effective in large systems. On a machine equipped > > > > with 1TB of memory and two NUMA nodes, the time for hugetlb > > > > initialization was reduced from 2 seconds to 1 second. > > > > > > Sorry to say, but why is that a scenario worth adding complexity for / > > > optimizing for? You don't cover that, so there is a clear lack in the > > > motivation. > > > > > > 2 vs. 1 second on a 1 TiB system is usually really just noise. > > > > > > > The cost will continue to grow over time, so I presume that Gang is trying > > to get out in front of the issue even though it may not be a large savings > > today. > > > > Running single boot tests, with the latest upstream kernel, allocating > > 1,440 1GB hugetlb pages on a 1.5TB AMD host appears to take 1.47s. > > > > But allocating 11,776 1GB hugetlb pages on a 12TB Intel host takes 65.2s > > today with the current implementation. > > And there, the 65.2s won't be noise because that 12TB system is up by a snap > of a finger? :) > In this single boot test, total boot time was 373.78s, so 1GB hugetlb allocation is 17.4% of that. Would love to see what the numbers would look like if 1GB pages were supported.
