search for: 16vcpu

...; > the prev head value will include the slowpath flag and indicate if we > > need to do PV kicking of suspended spinners -- on modern chips xadd > > isn't (much) more expensive than an add + load. > > > > Result: > > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > > benchmark overcommit %improve > > kernbench 1x -0.13 > > kernbench 2x 0.02 > > dbench 1x -1.77 > > dbench 2x -0.63 > > > > [Jeremy: hinted missing TICKET_LOCK_INC for kick] > > [Oleg:...

...; > the prev head value will include the slowpath flag and indicate if we > > need to do PV kicking of suspended spinners -- on modern chips xadd > > isn't (much) more expensive than an add + load. > > > > Result: > > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > > benchmark overcommit %improve > > kernbench 1x -0.13 > > kernbench 2x 0.02 > > dbench 1x -1.77 > > dbench 2x -0.63 > > > > [Jeremy: hinted missing TICKET_LOCK_INC for kick] > > [Oleg:...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...ter-release by using xadd; > the prev head value will include the slowpath flag and indicate if we > need to do PV kicking of suspended spinners -- on modern chips xadd > isn't (much) more expensive than an add + load. > > Result: > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > benchmark overcommit %improve > kernbench 1x -0.13 > kernbench 2x 0.02 > dbench 1x -1.77 > dbench 2x -0.63 > > [Jeremy: hinted missing TICKET_LOCK_INC for kick] > [Oleg: Moving slowpath flag to head, ticke...

...ter-release by using xadd; > the prev head value will include the slowpath flag and indicate if we > need to do PV kicking of suspended spinners -- on modern chips xadd > isn't (much) more expensive than an add + load. > > Result: > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > benchmark overcommit %improve > kernbench 1x -0.13 > kernbench 2x 0.02 > dbench 1x -1.77 > dbench 2x -0.63 > > [Jeremy: hinted missing TICKET_LOCK_INC for kick] > [Oleg: Moving slowpath flag to head, ticke...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...ter-release by using xadd; > the prev head value will include the slowpath flag and indicate if we > need to do PV kicking of suspended spinners -- on modern chips xadd > isn't (much) more expensive than an add + load. > > Result: > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > benchmark overcommit %improve > kernbench 1x -0.13 > kernbench 2x 0.02 > dbench 1x -1.77 > dbench 2x -0.63 > > [Jeremy: hinted missing TICKET_LOCK_INC for kick] > [Oleg: Moving slowpath flag to head, ticket_eq...

...ter-release by using xadd; > the prev head value will include the slowpath flag and indicate if we > need to do PV kicking of suspended spinners -- on modern chips xadd > isn't (much) more expensive than an add + load. > > Result: > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > benchmark overcommit %improve > kernbench 1x -0.13 > kernbench 2x 0.02 > dbench 1x -1.77 > dbench 2x -0.63 > > [Jeremy: hinted missing TICKET_LOCK_INC for kick] > [Oleg: Moving slowpath flag to head, ticket_eq...

...e will include the slowpath flag and indicate if we > > > need to do PV kicking of suspended spinners -- on modern chips xadd > > > isn't (much) more expensive than an add + load. > > > > > > Result: > > > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > > > benchmark overcommit %improve > > > kernbench 1x -0.13 > > > kernbench 2x 0.02 > > > dbench 1x -1.77 > > > dbench 2x -0.63 > > > > > > [Jeremy: hinted missing TICKET_...

...e will include the slowpath flag and indicate if we > > > need to do PV kicking of suspended spinners -- on modern chips xadd > > > isn't (much) more expensive than an add + load. > > > > > > Result: > > > setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) > > > benchmark overcommit %improve > > > kernbench 1x -0.13 > > > kernbench 2x 0.02 > > > dbench 1x -1.77 > > > dbench 2x -0.63 > > > > > > [Jeremy: hinted missing TICKET_...

...head value will include the slowpath flag and indicate if we >>> need to do PV kicking of suspended spinners -- on modern chips xadd >>> isn't (much) more expensive than an add + load. >>> >>> Result: >>> setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) >>> benchmark overcommit %improve >>> kernbench 1x -0.13 >>> kernbench 2x 0.02 >>> dbench 1x -1.77 >>> dbench 2x -0.63 >>> >>> [Jeremy: hinted missing TICKET_LOCK_INC f...

...head value will include the slowpath flag and indicate if we >>> need to do PV kicking of suspended spinners -- on modern chips xadd >>> isn't (much) more expensive than an add + load. >>> >>> Result: >>> setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) >>> benchmark overcommit %improve >>> kernbench 1x -0.13 >>> kernbench 2x 0.02 >>> dbench 1x -1.77 >>> dbench 2x -0.63 >>> >>> [Jeremy: hinted missing TICKET_LOCK_INC f...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...r avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] [PeterZ: Detailed changelog]...

...to lock after unlock(), and we can move slowpath clearing to fastpath lock. So this patch implements the fix with: 1. Moving slowpath flag to head (Oleg). 2. use xadd to avoid read/write after unlock that checks the need for unlock_kick (Linus). Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] Reported-by: Sasha Levin &lt...

...to lock after unlock(), and we can move slowpath clearing to fastpath lock. So this patch implements the fix with: 1. Moving slowpath flag to head (Oleg). 2. use xadd to avoid read/write after unlock that checks the need for unlock_kick (Linus). Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: hinted missing TICKET_LOCK_INC for kick] [Oleg: Moving slowpath flag to head, ticket_equals idea] Reported-by: Sasha Levin &lt...