From: Avi Kivity <avi@redhat.com>
To: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: linux-arch@vger.kernel.org, x86@kernel.org, arnd@arndb.de,
kvm@vger.kernel.org, kvm-ia64@vger.kernel.org,
fernando@oss.ntt.co.jp, mtosatti@redhat.com, agraf@suse.de,
kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org,
linuxppc-dev@ozlabs.org, mingo@redhat.com, paulus@samba.org,
hpa@zytor.com, tglx@linutronix.de,
Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Subject: Re: [RFC][PATCH 0/12] KVM, x86, ppc, asm-generic: moving dirty bitmaps to user space
Date: Thu, 13 May 2010 14:47:28 +0300 [thread overview]
Message-ID: <4BEBE6D0.8020000@redhat.com> (raw)
In-Reply-To: <4BE7FB7B.5010600@oss.ntt.co.jp>
On 05/10/2010 03:26 PM, Takuya Yoshikawa wrote:
>> No doubt get.org -> get.opt is measurable, but get.opt->switch.opt is
>> problematic. Have you tried profiling to see where the time is spent
>> (well I can guess, clearing the write access from the sptes).
>
>
> Sorry but no, and I agree with your guess.
> Anyway, I want to do some profiling to confirm this guess.
>
>
> BTW, If we only think about performance improvement of time, optimized
> get(get.opt) may be enough at this stage.
>
> But if we consider the future expansion like using user allocated
> bitmaps,
> new API's introduced for switch.opt won't become waste, I think,
> because we
> need a structure to get and export bitmap addresses.
User allocated bitmaps have the advantage of reducing pinned memory.
However we have plenty more pinned memory allocated in memory slots, so
by itself, user allocated bitmaps don't justify this change.
Perhaps if we optimize memory slot write protection (I have some ideas
about this) we can make the performance improvement more pronounced.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-05-13 11:47 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-04 12:56 [RFC][PATCH 0/12] KVM, x86, ppc, asm-generic: moving dirty bitmaps to user space Takuya Yoshikawa
2010-05-04 12:58 ` [RFC][PATCH 1/12 applied today] KVM: x86: avoid unnecessary bitmap allocation when memslot is clean Takuya Yoshikawa
2010-05-04 13:00 ` [RFC][PATCH 2/12] KVM: introduce slot level dirty state management Takuya Yoshikawa
2010-05-04 13:01 ` [RFC][PATCH 3/12] KVM: introduce wrapper functions to create and destroy dirty bitmaps Takuya Yoshikawa
2010-05-04 13:02 ` [RFC][PATCH 4/12] x86: introduce copy_in_user() for 32-bit Takuya Yoshikawa
2010-05-04 13:02 ` [RFC][PATCH 5/12] x86: introduce __set_bit() like function for bitmaps in user space Takuya Yoshikawa
2010-05-04 13:03 ` [RFC][PATCH 6/12 not tested yet] PPC: introduce copy_in_user() for 32-bit Takuya Yoshikawa
2010-05-04 13:04 ` [RFC][PATCH 7/12 not tested yet] PPC: introduce __set_bit() like function for bitmaps in user space Takuya Yoshikawa
2010-05-11 16:00 ` Alexander Graf
2010-05-12 9:25 ` Takuya Yoshikawa
2010-05-04 13:05 ` [RFC][PATCH resend 8/12] asm-generic: bitops: introduce le bit offset macro Takuya Yoshikawa
2010-05-04 15:03 ` Arnd Bergmann
2010-05-04 16:08 ` Avi Kivity
2010-05-05 2:59 ` Takuya Yoshikawa
2010-05-06 13:38 ` Arnd Bergmann
2010-05-10 11:46 ` Takuya Yoshikawa
2010-05-10 12:01 ` Avi Kivity
2010-05-10 12:01 ` Arnd Bergmann
2010-05-10 12:09 ` Takuya Yoshikawa
2010-05-04 13:06 ` [RFC][PATCH 9/12] KVM: introduce a wrapper function of set_bit_user_non_atomic() Takuya Yoshikawa
2010-05-04 13:07 ` [RFC][PATCH RFC 10/12] KVM: move dirty bitmaps to user space Takuya Yoshikawa
2010-05-11 3:28 ` Marcelo Tosatti
2010-05-12 6:27 ` Takuya Yoshikawa
2010-05-04 13:08 ` [RFC][PATCH 11/12] KVM: introduce new API for getting/switching dirty bitmaps Takuya Yoshikawa
2010-05-11 3:43 ` Marcelo Tosatti
2010-05-11 5:53 ` Takuya Yoshikawa
2010-05-11 14:07 ` Marcelo Tosatti
2010-05-12 6:03 ` Takuya Yoshikawa
2010-05-04 13:11 ` [RFC][PATCH 12/12 sample] qemu-kvm: use " Takuya Yoshikawa
2010-05-10 12:06 ` [RFC][PATCH 0/12] KVM, x86, ppc, asm-generic: moving dirty bitmaps to user space Avi Kivity
2010-05-10 12:26 ` Takuya Yoshikawa
2010-05-11 10:11 ` Takuya Yoshikawa
2010-05-13 11:47 ` Avi Kivity [this message]
2010-05-17 9:06 ` Takuya Yoshikawa
2010-05-11 15:55 ` Alexander Graf
2010-05-12 9:19 ` Takuya Yoshikawa
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