From: Peter Zijlstra <peterz@infradead.org>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Hugh Dickins <hughd@google.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
x86@kernel.org
Subject: Re: [RFC 0/6] x86: prefetch_page() vDSO call
Date: Thu, 25 Feb 2021 10:55:00 +0100 [thread overview]
Message-ID: <YDdz9JwcwuqV3GaW@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <D3DF6AC2-679F-4E64-B511-B1A03D1C6048@gmail.com>
On Thu, Feb 25, 2021 at 01:32:56AM -0800, Nadav Amit wrote:
> > On Feb 25, 2021, at 12:52 AM, Nadav Amit <nadav.amit@gmail.com> wrote:
> > Can you give me a reference to the “removing explicit prefetch from some
> > parts of the kernel”?
75d65a425c01 ("hlist: remove software prefetching in hlist iterators")
e66eed651fd1 ("list: remove prefetching from regular list iterators")
> Oh. I get it - you mean we remove we remove the use of explicit memory
> prefetch from the kernel code. Well, I don’t think it is really related,
> but yes, performance numbers are needed.
Right, so my main worry was that use of the prefetch instruction
actually hurt performance once the hardware prefetchers got smart
enough, this being a very similar construct (just on a different level
of the stack) should be careful not to suffer the same fate.
next prev parent reply other threads:[~2021-02-25 9:55 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 7:29 Nadav Amit
2021-02-25 7:29 ` [RFC 1/6] vdso/extable: fix calculation of base Nadav Amit
2021-02-25 21:16 ` Sean Christopherson
2021-02-26 17:24 ` Nadav Amit
2021-02-26 17:47 ` Sean Christopherson
2021-02-28 9:20 ` Nadav Amit
2021-02-25 7:29 ` [RFC 2/6] x86/vdso: add mask and flags to extable Nadav Amit
2021-02-25 7:29 ` [RFC 3/6] x86/vdso: introduce page_prefetch() Nadav Amit
2021-02-25 7:29 ` [RFC 4/6] mm/swap_state: respect FAULT_FLAG_RETRY_NOWAIT Nadav Amit
2021-02-25 7:29 ` [RFC 5/6] mm: use lightweight reclaim on FAULT_FLAG_RETRY_NOWAIT Nadav Amit
2021-02-25 7:29 ` [PATCH 6/6] testing/selftest: test vDSO prefetch_page() Nadav Amit
2021-02-25 8:40 ` [RFC 0/6] x86: prefetch_page() vDSO call Peter Zijlstra
2021-02-25 8:52 ` Nadav Amit
2021-02-25 9:32 ` Nadav Amit
2021-02-25 9:55 ` Peter Zijlstra [this message]
2021-02-25 12:16 ` Matthew Wilcox
2021-02-25 16:56 ` Nadav Amit
2021-02-25 17:32 ` Matthew Wilcox
2021-02-25 17:53 ` Nadav Amit
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