[dm-devel] [PATCH v2 RESEND] x86: optimize memcpy_flushcache

Ingo Molnar mingo at kernel.org
Thu Jun 21 14:31:40 UTC 2018


* Mike Snitzer <snitzer at redhat.com> wrote:

> From: Mikulas Patocka <mpatocka at redhat.com>
> Subject: [PATCH v2] x86: optimize memcpy_flushcache
> 
> In the context of constant short length stores to persistent memory,
> memcpy_flushcache suffers from a 2% performance degradation compared to
> explicitly using the "movnti" instruction.
> 
> Optimize 4, 8, and 16 byte memcpy_flushcache calls to explicitly use the
> movnti instruction with inline assembler.

Linus requested asm optimizations to include actual benchmarks, so it would be 
nice to describe how this was tested, on what hardware, and what the before/after 
numbers are.

Thanks,

	Ingo




More information about the dm-devel mailing list