From: "Arnd Bergmann" <arnd@arndb.de>
To: "Adrian Hunter" <adrian.hunter@intel.com>,
"Thomas Gleixner" <tglx@linutronix.de>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"John Stultz" <jstultz@google.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Alexander Gordeev" <agordeev@linux.ibm.com>,
"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
linux-s390@vger.kernel.org, x86@kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
"Christian Borntraeger" <borntraeger@linux.ibm.com>,
"Vasily Gorbik" <gor@linux.ibm.com>,
"Heiko Carstens" <hca@linux.ibm.com>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Borislav Petkov" <bp@alien8.de>,
"Andy Lutomirski" <luto@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Anna-Maria Gleixner" <anna-maria@linutronix.de>,
"Stephen Boyd" <sboyd@kernel.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
linux-kernel@vger.kernel.org,
"Sven Schnelle" <svens@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH V2 00/19] timekeeping: Handle potential multiplication overflow
Date: Mon, 25 Mar 2024 19:11:21 +0100 [thread overview]
Message-ID: <64804d62-1946-4cde-aea1-e8bab0860bfc@app.fastmail.com> (raw)
In-Reply-To: <20240325064023.2997-1-adrian.hunter@intel.com>
On Mon, Mar 25, 2024, at 07:40, Adrian Hunter wrote:
>
> Extend the facility also to VDSO, dependent on new config option
> GENERIC_VDSO_OVERFLOW_PROTECT which is selected by x86 only, so other
> architectures are not affected. The result is a calculation that has
> similar performance as before. Most machines showed performance benefit,
> except Skylake-based hardware such as Intel Kaby Lake which was seen <1%
> worse.
I've read through the series, and this pretty much all makes sense,
nice work!
There are a few patches that just rearrange the local variable
declarations to save a few lines, and I don't see those as an
improvement, but they also don't hurt aside from distracting
slightly from the real changes.
Arnd
prev parent reply other threads:[~2024-03-25 18:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-25 6:40 [PATCH V2 00/19] timekeeping: Handle potential multiplication overflow Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 01/19] vdso: Consolidate vdso_calc_delta() Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 02/19] vdso: Consolidate nanoseconds calculation Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 03/19] vdso: Add CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 04/19] math64: Tidy mul_u64_u32_shr() Adrian Hunter
2024-04-24 15:11 ` Peter Zijlstra
2024-03-25 6:40 ` [PATCH V2 05/19] vdso: math64: Provide mul_u64_u32_add_u64_shr() Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 06/19] vdso: Add vdso_data::max_cycles Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 07/19] vdso: Make delta calculation overflow safe Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 08/19] x86/vdso: " Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 09/19] timekeeping: Move timekeeping helper functions Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 10/19] timekeeping: Rename fast_tk_get_delta_ns() to __timekeeping_get_ns() Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 11/19] timekeeping: Tidy timekeeping_cycles_to_ns() slightly Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 12/19] timekeeping: Reuse timekeeping_cycles_to_ns() Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 13/19] timekeeping: Refactor timekeeping helpers Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 14/19] timekeeping: Consolidate " Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 15/19] timekeeping: Fold in timekeeping_delta_to_ns() Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 16/19] timekeeping: Prepare timekeeping_cycles_to_ns() for overflow safety Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 17/19] timekeeping: Make delta calculation overflow safe Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 18/19] timekeeping: Let timekeeping_cycles_to_ns() handle both under and overflow Adrian Hunter
2024-03-25 6:40 ` [PATCH V2 19/19] clocksource: Make watchdog and suspend-timing multiplication overflow safe Adrian Hunter
2024-03-25 18:11 ` Arnd Bergmann [this message]
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