Re: [PATCH] spapr: avoid overhead of finding vhyp class in critical operations

2024-03-12 Thread Nicholas Piggin
On Tue Mar 12, 2024 at 6:56 PM AEST, Harsh Prateek Bora wrote: > > > On 3/12/24 14:18, Nicholas Piggin wrote: > > On Tue Mar 12, 2024 at 4:38 PM AEST, Harsh Prateek Bora wrote: > >> Hi Nick, > >> > >> One minor comment below: > >> > >> On 2/24/24 13:03, Nicholas Piggin wrote: > >>>

Re: [PATCH] spapr: avoid overhead of finding vhyp class in critical operations

2024-03-12 Thread Harsh Prateek Bora
On 3/12/24 14:18, Nicholas Piggin wrote: On Tue Mar 12, 2024 at 4:38 PM AEST, Harsh Prateek Bora wrote: Hi Nick, One minor comment below: On 2/24/24 13:03, Nicholas Piggin wrote: PPC_VIRTUAL_HYPERVISOR_GET_CLASS is used in critical operations like interrupts and TLB misses and is quite

Re: [PATCH] spapr: avoid overhead of finding vhyp class in critical operations

2024-03-12 Thread Nicholas Piggin
On Tue Mar 12, 2024 at 4:38 PM AEST, Harsh Prateek Bora wrote: > Hi Nick, > > One minor comment below: > > On 2/24/24 13:03, Nicholas Piggin wrote: > > PPC_VIRTUAL_HYPERVISOR_GET_CLASS is used in critical operations like > > interrupts and TLB misses and is quite costly. Running the > >

Re: [PATCH] spapr: avoid overhead of finding vhyp class in critical operations

2024-03-12 Thread Harsh Prateek Bora
Hi Nick, One minor comment below: On 2/24/24 13:03, Nicholas Piggin wrote: PPC_VIRTUAL_HYPERVISOR_GET_CLASS is used in critical operations like interrupts and TLB misses and is quite costly. Running the kvm-unit-tests sieve program with radix MMU enabled thrashes the TCG TLB and spends a lot

Re: [PATCH] spapr: avoid overhead of finding vhyp class in critical operations

2024-02-25 Thread David Gibson
On Sat, Feb 24, 2024 at 05:33:59PM +1000, Nicholas Piggin wrote: > PPC_VIRTUAL_HYPERVISOR_GET_CLASS is used in critical operations like > interrupts and TLB misses and is quite costly. Running the > kvm-unit-tests sieve program with radix MMU enabled thrashes the TCG > TLB and spends a lot of time

[PATCH] spapr: avoid overhead of finding vhyp class in critical operations

2024-02-23 Thread Nicholas Piggin
PPC_VIRTUAL_HYPERVISOR_GET_CLASS is used in critical operations like interrupts and TLB misses and is quite costly. Running the kvm-unit-tests sieve program with radix MMU enabled thrashes the TCG TLB and spends a lot of time in TLB and page table walking code. The test takes 67 seconds to