Subject: [PATCH -perfbook] cpu: Add a QQz citing table E.1 An email thread started from a question from Leo [1] stimulated me to add a QQz on Paul's experience back in 2009. Link: [1] https://www.spinics.net/lists/perfbook/msg03824.html Signed-off-by: Akira Yokosawa <akiyks@xxxxxxxxx> --- I wrote: > On second thought, it should be possible to put a QQz next to QQz 3.7 > citing Table E.1 in the Quiz part. > > Let me try and produce a PoC patch. Something like this? I couldn't make the QQz next to QQz 3.7 due to the \QuickQuizLabel{\QspeedOfLightAtoms} just below QQz 3.7. If you put the label in the middle of \QuickQuizSeries{ ... } , you will get build errors in -nq builds. Instead, I added it next to QQz 3.8 (or the end of Section 3.2.2). It looks still relevant there. The wording of the Quiz and its Answer is just a stub. Paul, feel free to rewrite them as you like. Thanks, Akira -- cpu/overheads.tex | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/cpu/overheads.tex b/cpu/overheads.tex index 0d8270bf6e17..cff847cdadbf 100644 --- a/cpu/overheads.tex +++ b/cpu/overheads.tex @@ -485,10 +485,11 @@ cycles, as shown in the ``Global Comms'' row. % page 6/76 'Leading Interconnect, Leading Performance' % Needs updating... -\QuickQuiz{ +\QuickQuizSeries{% +\QuickQuizB{ These numbers are insanely large! How can I possibly get my head around them? -}\QuickQuizAnswer{ +}\QuickQuizAnswerB{ Get a roll of toilet paper. In the USA, each roll will normally have somewhere around 350--500 sheets. @@ -516,7 +517,24 @@ cycles, as shown in the ``Global Comms'' row. You might wish to avoid disabling interrupts across that many cache misses.\footnote{ Kudos to Matthew Wilcox for this holding-breath analogy.} -}\QuickQuizEnd +}\QuickQuizEndB +% +\QuickQuizE{ + \Cref{tab:cpu:Performance of Synchronization Mechanisms on 16-CPU 2.8GHz Intel X5550 (Nehalem) System} + in the answer to \QuickQuizARef{\QspeedOfLightAtoms} says that + In-Core CAS is faster than both of Same-CPU CAS and In-Core Blind CAS\@. + What is happening there? +}\QuickQuizAnswerE{ + I \emph{was} surprised by the data I obtained and did a rigorous + check of their validity. + I got the same result persistently. + One theory that might explain the observation would be: + The two threads in the core are able to overlap their accesses, + while the single CPU must do everything sequentially. + Unfortunately, there seems to be no public documentation explaining + why the Intel X5550 (Nehalem) system behaved like that. +}\QuickQuizEndE +} % End of \QuickQuizSeries \subsection{Hardware Optimizations} \label{sec:cpu:Hardware Optimizations} base-commit: 14440e232cc1b2580dc1a73f873dc29fe3aea02b -- 2.25.1
