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From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
To: ak@linux.intel.com
Cc: a.p.zijlstra@chello.nl, alex.shi@intel.com, mgorman@suse.de,
	npiggin@gmail.com, tglx@linutronix.de, mingo@redhat.com,
	hpa@zytor.com, arnd@arndb.de, rostedt@goodmis.org,
	fweisbec@gmail.com, jeremy@goop.org, gregkh@linuxfoundation.org,
	glommer@redhat.com, riel@redhat.com, luto@mit.edu,
	avi@redhat.com, len.brown@intel.com, dhowells@redhat.com,
	fenghua.yu@intel.com, borislav.petkov@amd.com,
	yinghai@kernel.org, cpw@sgi.com, steiner@sgi.com,
	akpm@linux-foundation.org, penberg@kernel.org, hughd@google.com,
	rientjes@google.com, kosaki.motohiro@jp.fujitsu.com,
	n-horiguchi@ah.jp.nec.com, paul.gortmaker@windriver.com,
	trenn@suse.de, tj@kernel.org, oleg@redhat.com, axboe@kernel.dk,
	kamezawa.hiroyu@jp.fujitsu.com, viro@zeniv.linux.org.uk,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] TLB flush optimization
Date: Thu, 10 May 2012 16:49:06 +0900 (JST)	[thread overview]
Message-ID: <20120510.164906.434297150.d.hatayama@jp.fujitsu.com> (raw)
In-Reply-To: <20120509234512.GA27196@tassilo.jf.intel.com>

From: Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v3] TLB flush optimization
Date: Wed, 9 May 2012 16:45:12 -0700

>> Have you tried what happens if you get rid of the funny multi-vector-ipi
>> scheme and use the generic smp_call functions?
> 
> Yes we did. It's much faster on larger systems.
> 
> But haven't sent the patch yet because wasn't sure if it wasn't slower
> on small systems.
> 
> -Andi

I'm not sure the reason of performance gain. I'm guessing that the
performance gain depends on waiting time of specific multi-vector-ipi
vs wasting time of generic code consumed for the processing actually
unnecessary for TLB flushing, and on small systems the specific one is
shorter than the generic one, and on large systems the converse
holds. Is this correct?

Thanks.
HATAYAMA, Daisuke


      parent reply	other threads:[~2012-05-10  7:51 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-08 14:03 Alex Shi
2012-05-08 14:03 ` [PATCH v3 1/7] x86/tlb_info: get last level TLB entry number of CPU Alex Shi
2012-05-08 14:03 ` [PATCH v3 2/7] x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range Alex Shi
2012-05-08 14:03 ` [PATCH v3 3/7] x86/tlb: fall back to flush all when meet a THP large page Alex Shi
2012-05-08 14:03 ` [PATCH v3 4/7] x86/tlb: add tlb flush all factor for specific CPUs Alex Shi
2012-05-08 15:08   ` Peter Zijlstra
2012-05-09  2:03     ` Alex Shi
2012-05-08 15:12   ` H. Peter Anvin
2012-05-09  2:10     ` Alex Shi
2012-05-08 15:15   ` H. Peter Anvin
2012-05-08 15:56     ` Andi Kleen
2012-05-08 16:40       ` H. Peter Anvin
2012-05-08 15:18   ` H. Peter Anvin
2012-05-09  1:41     ` Alex Shi
2012-05-08 14:03 ` [PATCH v3 5/7] x86/tlb: remove comments for tlb_flush_range implement suggestion Alex Shi
2012-05-09  8:22   ` Nick Piggin
2012-05-08 14:03 ` [PATCH v3 6/7] x86/tlb: optimizing flush_tlb_mm Alex Shi
2012-05-08 15:09   ` Peter Zijlstra
2012-05-08 14:03 ` [PATCH v3 7/7] x86/tlb: add tlb_flushall_factor into sysfs for user change Alex Shi
2012-05-08 15:11   ` Peter Zijlstra
2012-05-08 15:20     ` H. Peter Anvin
2012-05-08 15:25       ` Borislav Petkov
2012-05-08 15:31         ` H. Peter Anvin
2012-05-08 15:41           ` Borislav Petkov
2012-05-08 15:48             ` H. Peter Anvin
2012-05-08 16:10               ` Greg KH
2012-05-08 16:28                 ` Borislav Petkov
2012-05-09  5:03               ` Alex Shi
2012-05-08 15:01 ` [PATCH v3] TLB flush optimization Peter Zijlstra
2012-05-09  1:58   ` Alex Shi
2012-05-09 23:45   ` Andi Kleen
2012-05-10  5:06     ` Alex Shi
2012-05-10  7:49     ` HATAYAMA Daisuke [this message]

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