From: Peter Zijlstra <peterz@infradead.org>
To: Donghai Qiao <dqiao@redhat.com>
Cc: akpm@linux-foundation.org, sfr@canb.auug.org.au, arnd@arndb.de,
heying24@huawei.com, andriy.shevchenko@linux.intel.com,
axboe@kernel.dk, rdunlap@infradead.org, tglx@linutronix.de,
gor@linux.ibm.com, donghai.w.qiao@gmail.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 04/11] smp: replace smp_call_function_single() with smp_call()
Date: Mon, 25 Apr 2022 11:33:17 +0200 [thread overview]
Message-ID: <20220425093317.GF2731@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20220422200040.93813-5-dqiao@redhat.com>
On Fri, Apr 22, 2022 at 04:00:33PM -0400, Donghai Qiao wrote:
> Eliminated the percpu global csd_data and temporarily hook up
> to smp_call().
>
> There is no obvious reason or evidence that the differentiation
Using the on-stack csd seems like an obvious benefit to me. Stack is
often cache-hot, while the percpu stuff is likely a cache-miss. Worse,
the call_function_data as used by the mask functions is likely a double
miss due to the O(n^2) nature of the thing.
next prev parent reply other threads:[~2022-04-25 9:37 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-22 20:00 [PATCH v2 00/11] smp: cross CPU call interface Donghai Qiao
2022-04-22 20:00 ` [PATCH v2 01/11] smp: consolidate the structure definitions to smp.h Donghai Qiao
2022-04-23 4:57 ` kernel test robot
2022-04-25 8:39 ` Peter Zijlstra
2022-04-25 9:52 ` Thomas Gleixner
2022-04-22 20:00 ` [PATCH v2 02/11] smp: define the cross call interface Donghai Qiao
2022-04-25 9:05 ` Peter Zijlstra
2022-04-22 20:00 ` [PATCH v2 03/11] smp: eliminate SCF_WAIT and SCF_RUN_LOCAL Donghai Qiao
2022-04-25 9:10 ` Peter Zijlstra
2022-04-22 20:00 ` [PATCH v2 04/11] smp: replace smp_call_function_single() with smp_call() Donghai Qiao
2022-04-25 9:33 ` Peter Zijlstra [this message]
2022-04-22 20:00 ` [PATCH v2 05/11] smp: replace smp_call_function_single_async() with smp_call_private() Donghai Qiao
2022-04-23 7:30 ` kernel test robot
2022-04-24 22:06 ` Nathan Chancellor
2022-04-25 9:35 ` Peter Zijlstra
2022-04-22 20:00 ` [PATCH v2 06/11] smp: use smp_call_private() fron irq_work.c and core.c Donghai Qiao
2022-04-25 9:37 ` Peter Zijlstra
2022-04-22 20:00 ` [PATCH v2 07/11] smp: change smp_call_function_any() to smp_call_any() Donghai Qiao
2022-04-22 20:00 ` [PATCH v2 08/11] smp: replace smp_call_function_many_cond() with __smp_call_mask_cond() Donghai Qiao
2022-04-22 20:00 ` [PATCH v2 09/11] smp: replace smp_call_function_single_async with smp_call_private Donghai Qiao
2022-04-22 20:00 ` [PATCH v2 10/11] smp: replace smp_call_function_single() with smp_call() Donghai Qiao
2022-04-22 20:00 ` [PATCH v2 11/11] smp: modify up.c to adopt the same format of cross CPU call Donghai Qiao
2022-04-23 5:17 ` kernel test robot
2022-04-23 5:58 ` kernel test robot
2022-04-26 14:00 ` [PATCH v2 00/11] smp: cross CPU call interface Christoph Hellwig
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