Jun 2012 12:01:08 +0300
Subject: Re: [Qemu-devel] How to measure guest memory access
(qemu_ld/qemu_st) time?
On 06/19/2012 11:49 AM, 陳韋任 (Wei-Ren Chen) wrote:
Mind me CC this to ML? :)
sure I will read the threads to understand more.
Orit
Well it was a while back (2008-9) ,the company
://people.cs.nctu.edu.tw/~chenwj
-- Forwarded message --
From: Orit Wasserman owass...@redhat.com
To: \陳韋任 (Wei-Ren Chen)\ che...@iis.sinica.edu.tw
Cc:
Date: Tue, 19 Jun 2012 12:01:08 +0300
Subject: Re: [Qemu-devel] How to measure guest memory access
(qemu_ld/qemu_st) time?
On 06/19/2012 11
CC'ed to the mailing list.
--
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj
---BeginMessage---
On 06/19/2012 11:49 AM, 陳韋任 (Wei-Ren Chen) wrote:
Mind me CC
But if QEMU/TCG is doing a GVA-GPA translation as Wei-Ren said, I don't see
how
KVM can help.
Just want to clarify. QEMU maintain a TLB (env-tlb_table) which stores GVA -
HVA mapping, it is used to speedup the address translation. If TLB miss, QEMU
will call cpu_arm_handle_mmu_fault (take
On 06/19/2012 11:49 AM, 陳韋任 (Wei-Ren Chen) wrote:
Mind me CC this to ML? :)
sure I will read the threads to understand more.
Orit
Well it was a while back (2008-9) ,the company was acquired by IBM a year
later :
http://www.linux-kvm.org/wiki/images/9/98/KvmForum2008%24kdf2008_2.pdf
I
Michael Kang writes:
On Tue, Jun 19, 2012 at 4:26 AM, Lluís Vilanova vilan...@ac.upc.edu wrote:
[...]
I could understand having multiple 32bit regions in QEMU's virtual space (no
need for KVM), one per guest page table, and then simply adding an offset to
every memory access to redirect it to
On Tue, Jun 19, 2012 at 3:52 PM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
But if QEMU/TCG is doing a GVA-GPA translation as Wei-Ren said, I don't see
how
KVM can help.
Just want to clarify. QEMU maintain a TLB (env-tlb_table) which stores GVA
-
HVA mapping, it is used to
On Tue, Jun 19, 2012 at 4:26 AM, Lluís Vilanova vilan...@ac.upc.edu wrote:
Blue Swirl writes:
On Mon, Jun 18, 2012 at 8:28 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
The reason why we want to do the measuring is we want to use KVM (sounds
crazy
idea) MMU virtualization to
The idea looks nice, but instead of different TLB functions selected
at configure time, the optimization should be enabled by default.
Maybe a 'call' instruction could be used to jump to the slow path,
that way the slow path could be shared.
I don't understand what maybe a 'call'
The reason why we want to do the measuring is we want to use KVM (sounds
crazy
idea) MMU virtualization to speedup the guest - host memory address
translation.
I talked to some people on LinuxCon Japan, included Paolo, about this idea.
The
feedback I got is we can only use shadow page
On Mon, Jun 18, 2012 at 4:59 AM, YeongKyoon Lee
yeongkyoon@samsung.com wrote:
The idea looks nice, but instead of different TLB functions selected
at configure time, the optimization should be enabled by default.
Maybe a 'call' instruction could be used to jump to the slow path,
that way
On Mon, Jun 18, 2012 at 6:57 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
The idea looks nice, but instead of different TLB functions selected
at configure time, the optimization should be enabled by default.
Maybe a 'call' instruction could be used to jump to the slow path,
that
On Mon, Jun 18, 2012 at 8:28 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
The reason why we want to do the measuring is we want to use KVM (sounds
crazy
idea) MMU virtualization to speedup the guest - host memory address
translation.
I talked to some people on LinuxCon Japan,
陳韋任 (Wei-Ren Chen) writes:
The reason why we want to do the measuring is we want to use KVM (sounds
crazy
idea) MMU virtualization to speedup the guest - host memory address
translation.
I talked to some people on LinuxCon Japan, included Paolo, about this idea.
The
feedback I got is we
Blue Swirl writes:
On Mon, Jun 18, 2012 at 8:28 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
The reason why we want to do the measuring is we want to use KVM (sounds
crazy
idea) MMU virtualization to speedup the guest - host memory address
translation.
I talked to some people
The idea looks nice, but instead of different TLB functions selected
at configure time, the optimization should be enabled by default.
Maybe a 'call' instruction could be used to jump to the slow path,
that way the slow path could be shared.
I had considered the approach of sharing slow
On Fri, Jun 15, 2012 at 12:30 AM, Lluís Vilanova vilan...@ac.upc.edu wrote:
[...]
Now that I think of it, you will have problems generating code to surround
each
qemu_ld/st with a lightweight mechanism to get the time. In x86 it would be
rdtsc, but you want to generate a host rdtsc
Laurent Desnogues writes:
On Fri, Jun 15, 2012 at 12:30 AM, Lluís Vilanova vilan...@ac.upc.edu wrote:
[...]
Now that I think of it, you will have problems generating code to surround
each
qemu_ld/st with a lightweight mechanism to get the time. In x86 it would be
rdtsc, but you want to
path,
that way the slow path could be shared.
Thanks.
--- Original Message ---
Sender : 陳韋任 (Wei-Ren Chen)che...@iis.sinica.edu.tw
Date : 2012-06-14 12:31 (GMT+09:00)
Title : Re: [Qemu-devel] How to measure guest memory access (qemu_ld/qemu_st)
time?
As a side note, it might
sources.
Thanks.
--- Original Message ---
Sender : 陳韋任 (Wei-Ren Chen)che...@iis.sinica.edu.tw
Date : 2012-06-14 12:31 (GMT+09:00)
Title : Re: [Qemu-devel] How to measure guest memory access (qemu_ld/qemu_st)
time?
As a side note, it might be interesting to gather statistics about the hit
陳韋任 (Wei-Ren Chen) writes:
On Wed, Jun 13, 2012 at 12:43:28PM +0200, Laurent Desnogues wrote:
On Wed, Jun 13, 2012 at 5:14 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
Hi all,
I suspect that guest memory access (qemu_ld/qemu_st) account for the
major of
time spent in
陳韋任 (Wei-Ren Chen) writes:
Unfortunately, I had the bad idea of rebasing all my series on top of the
latest
makefile changes, and I'll have to go through each patch to check it's still
working (I'm sure some of them broke).
Need some help? :)
Well, it's just a matter of going through
Title: Samsung Enterprise Portal mySingle
I don't know much of instrumentation approach of Lluis, however, I had roughly estimated guest memory access (qemu_ld/st performance) overhead in legacy way last year.
My idea was indirect performanceestimation by measuring the generated host instruction
On Wed, Jun 13, 2012 at 4:14 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
I suspect that guest memory access (qemu_ld/qemu_st) account for the major of
time spent in system mode. I would like to know precisely how much (if
possible).
We use tools like perf [1] before, but since the
On Wed, Jun 13, 2012 at 5:14 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
Hi all,
I suspect that guest memory access (qemu_ld/qemu_st) account for the major of
time spent in system mode. I would like to know precisely how much (if
possible).
We use tools like perf [1] before, but
Stefan Hajnoczi writes:
On Wed, Jun 13, 2012 at 4:14 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
I suspect that guest memory access (qemu_ld/qemu_st) account for the major
of
time spent in system mode. I would like to know precisely how much (if
possible).
We use tools like
On Wed, Jun 13, 2012 at 12:43:28PM +0200, Laurent Desnogues wrote:
On Wed, Jun 13, 2012 at 5:14 AM, 陳韋任 (Wei-Ren Chen)
che...@iis.sinica.edu.tw wrote:
Hi all,
I suspect that guest memory access (qemu_ld/qemu_st) account for the major
of
time spent in system mode. I would like to know
Unfortunately, I had the bad idea of rebasing all my series on top of the
latest
makefile changes, and I'll have to go through each patch to check it's still
working (I'm sure some of them broke).
Need some help? :)
Regards,
chenwj
--
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute
As a side note, it might be interesting to gather statistics about the hit
rate of the QEMU TLB. Another thing to consider is speeding up the
fast path; see YeongKyoon Lee RFC patch:
http://www.mail-archive.com/qemu-devel@nongnu.org/msg91294.html
I only see PATCH 0/3, any idea on where
Hi all,
I suspect that guest memory access (qemu_ld/qemu_st) account for the major of
time spent in system mode. I would like to know precisely how much (if
possible).
We use tools like perf [1] before, but since the logic of guest memory access
aslo
embedded in the host binary not only
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