Elazar Leibovich | 25 Nov 21:56 2014
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How do I benchmark a spin lock?

The first question I have in mind, is, how do you define a lock benchmark? Is your goal to minimize overhead? Is your goal to minimize the latency of a successful uncontended acquire? Is your goal to minimize bus load for other CPU when three CPUs are waiting for the spin lock?


What we're measuring is not well defined.

Looking at [0] (wow, So little have changed in SMP architectures since 1990!) and [1], gives a few options:

1) Measure the time it takes to perform a critical section N times by n CPUs concurrently.
2) Measure overhead. Compare the time it takes to a single CPU to do a task N times with no locks. Do that with n CPUs, where the task is protected by a spin lock. The time it took to do the task with spinlock, minus the time it took to do it alone is the overhead.
3) Measure the overhead of other m CPUs doing a different task, while n CPUs are contending over a critical section.
4) Measure latency. This is a bit tricky to measure. What [1] suggests is, measure the average time between two spin locks read. If I understand that correctly, they measure the time it took to just check if the spinlock is taken.
5) What I had in mind, is measuring how much time did it took from the time a CPU released the lock, to the time another CPU held it. This is tricky to do, since CPUs clocks are not always synchronized or cheap enough to check.

The devil's in the details, so even though [1] have a bird's eye view description of the methodology, there are still missing details (e.g., did they measure time or cycles?).

I'm far from expert on this matters, so I wonder:

Is there an industry standard for benchmarking a spinlock? Something like JS octane. A benchmark which should mimic many real world scenarios?

If indeed there is, is there an open source implementation?

If there isn't, are there better papers describing spinlock benchmarking methodology?

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E.S. Rosenberg | 24 Nov 20:57 2014
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Linux install party <at> HUJI

There is currently some low key talk of arranging a linux install party for new students (and others interested) at Givat Ram.

Nothing specific as yet, the TA still needs to get back to us whether or not there is enough interest.

But I want to ask already if there is is enough interest are there people on the list interested in helping out?

Thanks,
Eliyahu - אליהו
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Amichai Rotman | 24 Nov 15:27 2014
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Recommended Router w/ADSL Modem

Can any of you recommend an off-the-shelf ADSL modem/router I can install OpenWRT on?

My current router is a Netgear DGN2200 by Bezezeq.

Thanks!

Amichai

Sent from my Galaxy S3

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Amichai Rotman | 23 Nov 21:45 2014
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Backdoor?

Hi All,

I am trying to troubleshoot a bottleneck in my internet connection.

I came across a few lines like these ones when I run 'netstat -ptW':

tcp        0      0 10.0.0.3:42239          82-166-201-152.barak-online.net:http ESTABLISHED 5881/chrome     
tcp        0      0 10.0.0.3:55224          bzq-179-180-121.static.bezeqint.net:https ESTABLISHED 5881/chrome     

I was once connected to these ISPs, but not for some time....

I have Netgear DGN2200 v2 provided by Bezeq, running firmware  V1.0.8.31_1.8.31.

Does Bezeq and the ISPs open a backdoor in my router somehow?

How can I find out exactly where I am connected and why?

Thanks!

Amichai
 
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Gabor Szabo | 19 Nov 10:38 2014

BYOD in schools

In our school the management is trying to implement BYOD = Bring Your Own Device 

Some details here:


First they talked about tablets but now it seems they talk about making us buy
notebooks.
Among many other issues, please note the technical requirements that gives us a choice of operating system:
Windows 7 or Windows 8

OTOH I could not find any information regarding the applications they want to run.

Do you have any information about similar projects in other schools in Israel?
What kind of devices have they used? What kind of applications do they install?

Gabor

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Shlomi Fish | 17 Nov 17:42 2014
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Fwd: Fw: [Qt-israel] Qt talk at the next FOSS Monthly meetup

Hi all,

we are going to have a monthly meetup about open source technologies on

Wednesday, November 26, 2014

in 18:30 at

Google Campus Tel Aviv, Electra Tower

Yigal Alon 98, Tel Aviv-Yafo (edit map)

More details below and at the link. Hope to see you there.

Regards,

-- Shlomi Fish

---------- Forwarded message ----------
From: Shlomi Fish <shlomif <at> shlomifish.org>
Date: Mon, Nov 17, 2014 at 6:40 PM
Subject: Fw: [Qt-israel] Qt talk at the next FOSS Monthly meetup
To: Shlomi Fish <shlomif-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>




Begin forwarded message:

Date: Mon, 17 Nov 2014 07:12:12 +0200
From: ynon perek <ynonperek <at> gmail.com>
To: Local Qt community <qt-israel-8fVK6v2op8h+3Tr40/nsqA@public.gmane.org>
Subject: [Qt-israel] Qt talk at the next FOSS Monthly meetup


Hi All,

In the next FOSS monthly meet up I'll talk about how to write multi
threaded code in Qt, and share some tips to make your life easier while
doing so.

Ido will give the second talk about development Anti-Patterns.

For details and registration please visit the event page:
http://www.meetup.com/Open-Source-and-Free-Software-in-Israel/events/218634223/

Regards,
  Ynon


--
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I figured wrong (with a capital R).
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Shlomi Fish http://www.shlomifish.org/

Chuck Norris helps the gods that help themselves.

Please reply to list if it's a mailing list post - http://shlom.in/reply .

Hi All,

In the next FOSS monthly meet up I'll talk about how to write multi threaded code in Qt, and share some tips to make your life easier while doing so. 

Ido will give the second talk about development Anti-Patterns.

For details and registration please visit the event page:

Regards,
  Ynon

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Oron Peled | 16 Nov 10:14 2014
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[JOB-OFFER] Linux devops people for embedded

Hi,

 

Below is a verbatim copy forwarded directly from the related company

please answer directly to them.

 

---------- Forwarded Message ----------

 

Do you breath, eat and drink LINUX?

If the answer is yes, HARMONIC IS LOOKING FOR YOU!

HARMONIC, the worldwide leader in video delivery infrastructure solutions

is offering a challenging position in DEVOPS development in our site in Caesarea.

 

So if you got passion to LINUX and want to specialize in a great atmosphere

and you answer the below requirements, please send us your CV to:

Jobs-VKpMlOibl5aqndwCJWfcng@public.gmane.org<mailto:Jobs-VKpMlOibl5aqndwCJWfcng@public.gmane.org>

 

* B.Sc in Computer science from a known university

* 0-3 years of experience in SW development

* 2-3 years of extensive experience in a LINUX environment and with C / C++ Programming

* Experience in DEVOPS development, Configuration Management (e.g. SVN), Scripting languages (e.g. Bash, Python) – advantage

 

For more information about Harmonic: http://www.harmonicinc.com/content/your-career-here

 

--

Oron Peled Voice: +972-4-8228492

oron <at> actcom.co.il http://users.actcom.co.il/~oron

 

Linux lasts longer!

-- "Kim J. Brand" <kim-4xDCiZgT6N5Wk0Htik3J/w@public.gmane.org>

 

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Eli Billauer | 15 Nov 17:56 2014
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[HAIFUX LECTURE] CiviCRM Meetup -- Xavier Dutoit

On Monday, November 17th at 18:30, Haifux will gather to hear a talk by Xavier Dutoit:

    CiviCRM Meetup

Abstract

CiviCRM is a free and open source software constituent relationship 
management solution. CiviCRM is web-based, internationalized, and 
designed specifically to meet the needs of advocacy and non-profit 
groups to manage their contacts, membership, donations & newsletter.

At this meeting you can learn more about what CiviCRM can do for your 
organisation, with examples of other NGOs, trade unions and 
associations. Meet others who are also interested in CiviCRM or who are 
already using it in their organisation. Talk to developers who know all 
about CiviCRM.

Note that the meeting will be held in *English*

    * Introduction to CiviCRM. What does it offer NGOs?
          o What's planned for the next version & info about CiviCon in
            San Francisco
    * Some examples of NGOs using CiviCRM
    * Possible uses of CiviCRM as seen in other NGOs:
          o Organising events
          o Doing emailings to the press/members...
          o Tracking advocacy actions, petitions & surveys
          o Membership & donations

=================================================================

We meet in Taub building, room 6. For instructions see:
http://www.haifux.org/where.html

Attendance is free, and you are all invited!

==================================================================
Future lectures:

01/12/14 Topics in advanced Python: Hai Zaar

==================================================================

We are always interested in hearing your talks and ideas. If you wish to give a talk, hold a discussion, or
just plan some event haifux might be interested in, please contact us at webmaster@...

--

-- 
Web: http://www.billauer.co.il

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Amichai Rotman | 13 Nov 13:33 2014
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LibraOffice and Language Switching

Hi all,

Since upgrading to LibraOffice 4.2 on my Ubuntu 14.04, I can´t use the CTRL-C and such if I am writing a document in Hebrew. 

On previous versions I could copy text using the keyboard regardless of the language I was using at the time.

Any ideas how to get that back?

Thanks!

Amichai.
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Constantine Shulyupin | 11 Nov 18:17 2014
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OCF CESA

Hi friends,

Has anybody experience with  openssl, ocf-linux and CESA on ARM Armaga 370?

Thanks
--

-- 
Constantine Shulyupin
http://www.MakeLinux.co.il/
Embedded Linux Systems
Tel Aviv

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E.S. Rosenberg | 10 Nov 11:06 2014
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OT: Jolla phone

Mords' mail reminded me that I should have sent this earlier:
If there is anyone on the list interested in getting the Jolla phone ('grandson' of the nokia n900/'son' of the n9) I have a 100E discount code that is valid until midnight today (I assume midnight Finland time, but it's not specified).

You do need an address in the EU to ship to, the phone is 249E after discount and shipping is another 15 I think...

Hope someont finds this useful.
Eliyahu - אליהו
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