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  • H. Peter Anvin's avatar
    x86: 32 bits: shrink and align IRQ stubs · b7c6244f
    H. Peter Anvin authored
    
    
    Shrink the IRQ stubs on 32 bits down to just over four bytes per (we
    fit seven into a 32-byte chunk.)  This shrinks the total icache
    consumption of the IRQ stubs down to an even kilobyte, if all of them
    are in active use.
    
    The downside is that we end up with a double jump, which could have a
    negative effect on some pipelines.  The double jump is always inside
    the same cacheline on any modern chips (the exception being
    486/Elan/Geode which have only 16-byte cachelines, but are unlikely to
    have too many interrupt sources.)
    
    To get the most effect, cache-align the IRQ stubs.
    
    Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
    b7c6244f