Speculation Barrier (SB) instruction can be used instead of a pair of DSB, ISB if supported. It should have better performance than DSB+ISB (https://developer.arm.com/documentation/102825/0100):

"... a DSB+ISB sequence is expected to have a significantly greater impact on performance than an SB ..."

Instruction support: https://developer.arm.com/documentation/109697/2025_03/Feature-descriptions/The-Armv8-5-architecture-extension

Speculation Barrier FEAT_SB introduces a barrier (SB) to control speculation.
This feature is supported in both AArch64 and AArch32 states.
FEAT_SB is OPTIONAL from Armv8.0.
FEAT_SB is mandatory from Armv8.5.