From: David Teigland <teigland@redhat.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Sasha Levin <levinsasha928@gmail.com>,
torvalds@linux-foundation.org, tj@kernel.org,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, paul.gortmaker@windriver.com,
davem@davemloft.net, rostedt@goodmis.org, mingo@elte.hu,
ebiederm@xmission.com, aarcange@redhat.com, ericvh@gmail.com,
netdev@vger.kernel.org, josh@joshtriplett.org,
eric.dumazet@gmail.com, axboe@kernel.dk, agk@redhat.com,
dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com,
Trond.Myklebust@netapp.com, bfields@fieldses.org,
fweisbec@gmail.com, jesse@nicira.com,
venkat.x.venkatsubra@oracle.com, ejt@redhat.com,
snitzer@redhat.com, edumazet@google.com,
linux-nfs@vger.kernel.org, dev@openvswitch.org,
rds-devel@oss.oracle.com, lw@cn.fujitsu.com
Subject: Re: [PATCH v7 10/16] dlm: use new hashtable implementation
Date: Mon, 29 Oct 2012 12:23:44 -0400 [thread overview]
Message-ID: <20121029162344.GC3516@redhat.com> (raw)
In-Reply-To: <20121029160710.GA18944@Krystal>
On Mon, Oct 29, 2012 at 12:07:10PM -0400, Mathieu Desnoyers wrote:
> I'm fine with turning a direct + modulo mapping into a dispersed hash as
> long as there are no underlying assumptions about sequentiality of value
> accesses.
>
> If the access pattern would happen to be typically sequential, then
> adding dispersion could hurt performances significantly, turning a
> frequent L1 access into a L2 access for instance.
> All I'm asking is: have you made sure that this hash table is not
> deliberately kept sequential (without dispersion) to accelerate specific
> access patterns ? This should at least be documented in the changelog.
It was not intentional. I don't expect any benefit would be lost by
making it non-sequential.
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WARNING: multiple messages have this Message-ID (diff)
From: David Teigland <teigland@redhat.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Sasha Levin <levinsasha928@gmail.com>,
torvalds@linux-foundation.org, tj@kernel.org,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, paul.gortmaker@windriver.com,
davem@davemloft.net, rostedt@goodmis.org, mingo@elte.hu,
ebiederm@xmission.com, aarcange@redhat.com, ericvh@gmail.com,
netdev@vger.kernel.org, josh@joshtriplett.org,
eric.dumazet@gmail.com, axboe@kernel.dk, agk@redhat.com,
dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com,
Trond.Myklebust@netapp.com, bfields@fieldses.org,
fweisbec@gmail.com, jesse@nicira.com,
venkat.x.venkatsubra@oracle.com, ejt@redhat.com,
snitzer@redhat.com, edumazet@google.com,
linux-nfs@vger.kernel.org, dev@openvswitch.org,
rds-devel@oss.oracle.com, lw@cn.fujitsu.com
Subject: Re: [PATCH v7 10/16] dlm: use new hashtable implementation
Date: Mon, 29 Oct 2012 12:23:44 -0400 [thread overview]
Message-ID: <20121029162344.GC3516@redhat.com> (raw)
In-Reply-To: <20121029160710.GA18944@Krystal>
On Mon, Oct 29, 2012 at 12:07:10PM -0400, Mathieu Desnoyers wrote:
> I'm fine with turning a direct + modulo mapping into a dispersed hash as
> long as there are no underlying assumptions about sequentiality of value
> accesses.
>
> If the access pattern would happen to be typically sequential, then
> adding dispersion could hurt performances significantly, turning a
> frequent L1 access into a L2 access for instance.
> All I'm asking is: have you made sure that this hash table is not
> deliberately kept sequential (without dispersion) to accelerate specific
> access patterns ? This should at least be documented in the changelog.
It was not intentional. I don't expect any benefit would be lost by
making it non-sequential.
next prev parent reply other threads:[~2012-10-29 16:23 UTC|newest]
Thread overview: 157+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-28 19:02 [PATCH v7 01/16] hashtable: introduce a small and naive hashtable Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` [PATCH v7 05/16] mm/huge_memory: use new hashtable implementation Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` [PATCH v7 06/16] tracepoint: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-29 11:35 ` Mathieu Desnoyers
2012-10-29 11:35 ` Mathieu Desnoyers
2012-10-29 17:29 ` Sasha Levin
2012-10-29 17:29 ` Sasha Levin
[not found] ` <CA+1xoqce6uJ6wy3+2CBwsLHKnsz4wD0vt8MBEGKCFfXTvuC0Hg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-29 17:50 ` Mathieu Desnoyers
2012-10-29 17:50 ` Mathieu Desnoyers
2012-10-29 17:50 ` Mathieu Desnoyers
2012-10-29 18:31 ` Josh Triplett
2012-10-29 18:31 ` Josh Triplett
2012-10-29 18:31 ` Josh Triplett
2012-10-29 18:42 ` Sasha Levin
2012-10-29 18:42 ` Sasha Levin
[not found] ` <CA+1xoqfMrn9zDFMJNFfA0NA86wE_DedD97cP1yJ2UQdTjs3uyQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-29 18:53 ` Mathieu Desnoyers
2012-10-29 18:53 ` Mathieu Desnoyers
2012-10-29 18:53 ` Mathieu Desnoyers
2012-10-29 18:58 ` Tejun Heo
2012-10-29 18:58 ` Tejun Heo
[not found] ` <20121029185814.GC4066-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-29 19:01 ` Tejun Heo
2012-10-29 19:01 ` Tejun Heo
2012-10-29 19:01 ` Tejun Heo
[not found] ` <20121029190107.GD4066-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-29 19:10 ` Mathieu Desnoyers
2012-10-29 19:10 ` Mathieu Desnoyers
2012-10-29 19:10 ` Mathieu Desnoyers
2012-10-29 19:09 ` Sasha Levin
2012-10-29 19:09 ` Sasha Levin
[not found] ` <CA+1xoqcSx04JEXy2aPu4Qt7Zb4iSqXBSjARgMae_FusgzpgnaQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-29 19:12 ` Tejun Heo
2012-10-29 19:12 ` Tejun Heo
2012-10-29 19:12 ` Tejun Heo
[not found] ` <20121029191256.GE4066-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-29 19:17 ` Sasha Levin
2012-10-29 19:17 ` Sasha Levin
2012-10-29 19:17 ` Sasha Levin
2012-10-29 19:16 ` Mathieu Desnoyers
2012-10-29 19:16 ` Mathieu Desnoyers
2012-10-28 19:02 ` [PATCH v7 08/16] block,elevator: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-29 1:29 ` Tejun Heo
2012-10-29 1:29 ` Tejun Heo
[not found] ` <1351450948-15618-8-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-10-29 12:20 ` Mathieu Desnoyers
2012-10-29 12:20 ` Mathieu Desnoyers
2012-10-29 12:20 ` Mathieu Desnoyers
2012-10-28 19:02 ` [PATCH v7 09/16] SUNRPC/cache: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-29 12:42 ` Mathieu Desnoyers
2012-10-29 12:42 ` Mathieu Desnoyers
2012-10-29 14:49 ` Linus Torvalds
2012-10-29 14:49 ` Linus Torvalds
2012-10-29 14:49 ` Linus Torvalds
2012-10-29 15:13 ` Mathieu Desnoyers
2012-10-29 15:13 ` Mathieu Desnoyers
2012-10-29 15:16 ` J. Bruce Fields
2012-10-29 15:16 ` J. Bruce Fields
[not found] ` <20121029151653.GC9502-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2012-10-29 15:41 ` Mathieu Desnoyers
2012-10-29 15:41 ` Mathieu Desnoyers
2012-10-29 15:41 ` Mathieu Desnoyers
[not found] ` <CA+55aFzO8DJJP3HBfgqXFac9r3=bYK+_nYe4cuXiNFg-623s6w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-29 16:27 ` Andrew Morton
2012-10-29 16:27 ` Andrew Morton
2012-10-29 16:27 ` Andrew Morton
2012-10-28 19:02 ` [PATCH v7 11/16] net,l2tp: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-29 13:04 ` Mathieu Desnoyers
2012-10-29 13:04 ` Mathieu Desnoyers
2012-10-28 19:02 ` [PATCH v7 13/16] lockd: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
[not found] ` <1351450948-15618-13-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-10-29 13:23 ` Mathieu Desnoyers
2012-10-29 13:23 ` Mathieu Desnoyers
2012-10-29 13:23 ` Mathieu Desnoyers
[not found] ` <1351450948-15618-1-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-10-28 19:02 ` [PATCH v7 02/16] userns: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` [PATCH v7 03/16] mm, ksm: " Sasha Levin
2012-10-28 19:02 ` [PATCH v7 03/16] mm,ksm: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` [PATCH v7 04/16] workqueue: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` Sasha Levin
[not found] ` <1351450948-15618-4-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-10-29 1:25 ` Tejun Heo
2012-10-29 1:25 ` Tejun Heo
2012-10-29 1:25 ` Tejun Heo
2012-10-28 19:02 ` [PATCH v7 07/16] net, 9p: " Sasha Levin
2012-10-28 19:02 ` [PATCH v7 07/16] net,9p: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
[not found] ` <1351450948-15618-7-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-10-29 12:15 ` [PATCH v7 07/16] net, 9p: " Mathieu Desnoyers
2012-10-29 12:15 ` [PATCH v7 07/16] net,9p: " Mathieu Desnoyers
2012-10-29 12:15 ` Mathieu Desnoyers
2012-10-28 19:02 ` [PATCH v7 10/16] dlm: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` Sasha Levin
[not found] ` <1351450948-15618-10-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-10-29 12:46 ` Mathieu Desnoyers
2012-10-29 12:46 ` Mathieu Desnoyers
2012-10-29 12:46 ` Mathieu Desnoyers
2012-10-29 13:07 ` Mathieu Desnoyers
2012-10-29 13:07 ` Mathieu Desnoyers
2012-10-29 15:53 ` Sasha Levin
2012-10-29 15:53 ` Sasha Levin
2012-10-29 15:53 ` Sasha Levin
2012-10-29 16:07 ` Mathieu Desnoyers
2012-10-29 16:07 ` Mathieu Desnoyers
2012-10-29 16:23 ` David Teigland [this message]
2012-10-29 16:23 ` David Teigland
2012-10-28 19:02 ` [PATCH v7 12/16] dm: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` [PATCH v7 14/16] net, rds: " Sasha Levin
2012-10-28 19:02 ` [PATCH v7 14/16] net,rds: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
[not found] ` <1351450948-15618-14-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-10-29 13:25 ` Mathieu Desnoyers
2012-10-29 13:25 ` Mathieu Desnoyers
2012-10-29 13:25 ` Mathieu Desnoyers
2012-10-28 19:02 ` [PATCH v7 15/16] openvswitch: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-29 13:29 ` Mathieu Desnoyers
2012-10-29 13:29 ` Mathieu Desnoyers
2012-10-29 15:43 ` Sasha Levin
2012-10-29 15:43 ` Sasha Levin
2012-10-29 15:43 ` Sasha Levin
[not found] ` <CA+1xoqfRGhPaBEVh228O5_295bWh8FmcyLSOwq8VE5Dm7i3JHg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-29 15:59 ` Mathieu Desnoyers
2012-10-29 15:59 ` Mathieu Desnoyers
2012-10-29 15:59 ` Mathieu Desnoyers
2012-10-29 17:35 ` Sasha Levin
2012-10-29 17:35 ` Sasha Levin
[not found] ` <CA+1xoqcr5xmOkDfqL3P84CNdotOALOhiLRkJjsPCZzijSQUF6w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-29 18:16 ` Mathieu Desnoyers
2012-10-29 18:16 ` Mathieu Desnoyers
2012-10-29 18:16 ` Mathieu Desnoyers
2012-10-29 18:22 ` Tejun Heo
2012-10-29 18:22 ` Tejun Heo
2012-10-29 18:22 ` Tejun Heo
[not found] ` <20121029182209.GB4066-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-29 18:35 ` Mathieu Desnoyers
2012-10-29 18:35 ` Mathieu Desnoyers
2012-10-29 18:35 ` Mathieu Desnoyers
2012-10-28 19:02 ` [PATCH v7 16/16] tracing output: " Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-28 19:02 ` Sasha Levin
2012-10-29 11:29 ` [PATCH v7 01/16] hashtable: introduce a small and naive hashtable Mathieu Desnoyers
2012-10-29 11:29 ` Mathieu Desnoyers
2012-10-29 16:06 ` Sasha Levin
2012-10-29 16:06 ` Sasha Levin
2012-10-29 16:14 ` Mathieu Desnoyers
2012-10-29 16:14 ` Mathieu Desnoyers
2012-10-29 16:18 ` Tejun Heo
2012-10-29 16:18 ` Tejun Heo
2012-10-29 16:18 ` Tejun Heo
2012-10-29 16:22 ` Mathieu Desnoyers
2012-10-29 16:22 ` Mathieu Desnoyers
2012-10-29 16:26 ` Sasha Levin
2012-10-29 16:26 ` Sasha Levin
[not found] ` <CA+1xoqfBXM4sjvcZtUncnWAaUxA9_YBod3Hjx3ZO=K1oJO_j7g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-29 16:29 ` Mathieu Desnoyers
2012-10-29 16:29 ` Mathieu Desnoyers
2012-10-29 16:29 ` Mathieu Desnoyers
-- strict thread matches above, loose matches on Subject: below --
2012-10-30 11:29 [PATCH v7 10/16] dlm: use new hashtable implementation Staci Page
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