spi: spi.c: Convert statistics to per-cpu u64_stats_t

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This change gives a dramatic performance improvement in the hot path,
since many costly spin_lock_irqsave() calls can be avoided.

On an i.MX8MM system with a MCP2518FD CAN controller connected via SPI,
the time the driver takes to handle interrupts, or in other words the time
the IRQ line of the CAN controller stays low is mainly dominated by the
time it takes to do 3 relatively short sync SPI transfers. The effect of
this patch is a reduction of this time from 136us down to only 98us.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220524091808.2269898-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>

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David Jander 2022-05-24 11:18:08 +02:00 • committed by Mark Brown

parent b658be56e8

commit 6598b91b5a

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2 changed files with 127 additions and 68 deletions

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143

drivers/spi/spi.c

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52

include/linux/spi/spi.h

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