From: Paul Campbell <taniwha@gmail.com>
To: linux-riscv@lists.infradead.org
Subject: Re: prefetchw()
Date: Sun, 27 Jun 2021 15:44:28 +1200 [thread overview]
Message-ID: <2035172.PIDvDuAF1L@rata> (raw)
In-Reply-To: <2623321.7s5MMGUR32@rata>
On Sunday, 27 June 2021 3:31:18 PM NZST Paul Campbell wrote:
> i noticed today that __builtin_prefetch() emits nothing (at least in my gcc)
>
> i wonder if it makes sense to do this for riscv linux?
>
> static inline void prefetchw( volatile void *addr)
> {
> asm volatile("lb x0, 0(%0)" : : "r" (addr));
> }
I should add that gcc __builtin_prefetch() promises not to fault while the
kernel prefetchw(), from my quick look through the code doesn't seem to depend
on that (in fact loops get unrolled in places to make sure)
Paul
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prev parent reply other threads:[~2021-06-27 3:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-27 3:31 prefetchw() Paul Campbell
2021-06-27 3:44 ` Paul Campbell [this message]
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