From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>,
Nicholas Piggin <npiggin@gmail.com>,
David Miller <davem@davemloft.net>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Anton Blanchard <anton@samba.org>,
linuxppc-dev list <linuxppc-dev@ozlabs.org>
Subject: Re: [RFC][PATCH] spin loop arch primitives for busy waiting
Date: Fri, 7 Apr 2017 11:43:49 +0200 [thread overview]
Message-ID: <20170407094349.f4hdqibbgl36s776@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CA+55aFzTn9e=F68SOtEvvZLdT6zCj9+gLc-OS7qhDKdM7zaasA@mail.gmail.com>
On Thu, Apr 06, 2017 at 10:31:46AM -0700, Linus Torvalds wrote:
> But maybe "monitor" is really cheap. I suspect it's microcoded,
> though, which implies "no".
On my IVB-EP (will also try on something newer):
MONITOR ~332 cycles
MWAIT ~224 cycles (C0, explicitly invalidated MONITOR)
So yes, expensive.
next prev parent reply other threads:[~2017-04-07 9:44 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-03 8:13 Nicholas Piggin
2017-04-03 15:31 ` Linus Torvalds
2017-04-03 23:50 ` Nicholas Piggin
2017-04-04 0:43 ` Linus Torvalds
2017-04-04 3:02 ` Nicholas Piggin
2017-04-04 4:11 ` Nicholas Piggin
2017-04-05 14:01 ` David Miller
2017-04-06 0:59 ` Nicholas Piggin
2017-04-06 14:13 ` Will Deacon
2017-04-06 15:16 ` Linus Torvalds
2017-04-06 16:36 ` Peter Zijlstra
2017-04-06 17:31 ` Linus Torvalds
2017-04-06 19:23 ` Peter Zijlstra
2017-04-06 19:41 ` Linus Torvalds
2017-04-07 3:31 ` Nicholas Piggin
2017-04-07 9:43 ` Peter Zijlstra [this message]
2017-04-07 11:26 ` Nicholas Piggin
2017-04-06 15:30 ` Nicholas Piggin
2017-04-07 16:13 ` Will Deacon
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