On 06/23/2018 12:22 PM, Douglas Gilbert wrote:
Add likely() and unlikely() hints to conditionals on or near the fastpath.
Signed-off-by: Douglas Gilbert <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
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A reviewer wanted any performance improvement (or otherwise) quantified.
The improvement was so small, that ftrace ignored it. Inline timing code
suggests the improvement from this whole patchset is around 7 nanoseconds
per invocation (tested on a Lenovo X270 (i5-7200U)). Not exactly huge.
Another win might be the smaller size of scsi_io_completion() after the
refactoring; this should allow more other code to fit in the instruction
cache.
Reviewed-by: Hannes Reinecke <[email protected]>
Cheers,
Hannes
