On 14. 08. 25, 10:22, Jiri Slaby wrote:
Hi,
On 12. 08. 25, 19:28, Greg Kroah-Hartman wrote:
6.16-stable review patch. If anyone has any objections, please let me know.
From: Peter Zijlstra peterz@infradead.org
[ Upstream commit cccb45d7c4295bbfeba616582d0249f2d21e6df5 ]
Chris reported that commit 5f6bd380c7bd ("sched/rt: Remove default bandwidth control") caused a significant dip in his favourite benchmark of the day. Simply disabling dl_server cured things.
His workload hammers the 0->1, 1->0 transitions, and the dl_server_{start,stop}() overhead kills it -- fairly obviously a bad idea in hind sight and all that.
Change things around to only disable the dl_server when there has not been a fair task around for a whole period. Since the default period is 1 second, this ensures the benchmark never trips this, overhead gone.
This causes: sched: DL replenish lagged too much
Maybe some prereq missing?
Not really, this is present both in linus/master and tip/master.
Fixes: 557a6bfc662c ("sched/fair: Add trivial fair server") Reported-by: Chris Mason clm@meta.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Juri Lelli juri.lelli@redhat.com Acked-by: Juri Lelli juri.lelli@redhat.com Link: https://lkml.kernel.org/r/20250702121158.465086194@infradead.org Signed-off-by: Sasha Levin sashal@kernel.org
thanks,