search for: embarrass

A few random observations: 1. Clang could do better with large but boring switches like this: http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/E8/E88C5111.shtml Performance of clang's output will be fine but this is a major code size lose. 2. Destruction of stupid loops is incomplete, sometimes due to phase ordering problems: http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/FC/FCADC848.shtml...

>> Repetitive code with lots of bitwise operations is compiled by LLVM into >> much larger code than the other compilers: >> >> http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/ED/ED37DAF5.shtml >> http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/1F/1F4003C7.shtml >> >> Note that this is straight-line code, so LLVM's output will run 4-5 >> times longer than everyone else's. >> >> I'll be i...

> Umm, can you find one that isn't a popcount implementation? Ok. MMX psadbw instruction: http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/CE/CE3DA132.shtml Position of first set bit: http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/1F/1F4003C7.shtml Log2 floor: http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/83/837A80E9.shtml Pixel format conversion: http://embed.cs.utah.edu/embar...

On Tue, Jan 26, 2010 at 12:36 PM, John Regehr <regehr at cs.utah.edu> wrote: > 2. > Sometimes not: > > http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/EC/ECC74C0C.shtml The primary issue here is that scalar evolution doesn't know how to deal with loops using "sle" for the exit condition. Shouldn't be too hard to fix now that we have overflow flags for addition. > 3. > > Repetitive code with l...

I have an "embarrassingly parallel" routine that I need to run 24000^2/2 times (based on some microarray data). All I really need to do is parallelize a nested for-loop. But I haven't found a clear list of what packages/commands I'd need to do this. I've got a dual quad core xeon system running RHEL...

...y values are count data, integers with Poisson distribution, and it is important for the regression function to know this, since assuming a Gaussian distribution will lead to substantial errors. It is a time series; the x values have equal five minute intervals. Here is the problem: I have an embarrassment of riches. Unless I am mistaken, the following R packages will do this: locfit, aws, sm, gss, semipar, pgam, gregmisc, to name just a few. Questions: Which package should I use, and which function in the package should I use for the regression? Here is the Google search result, restricted...

On Tue, Jan 26, 2010 at 5:55 PM, John Regehr <regehr at cs.utah.edu> wrote: >>> Repetitive code with lots of bitwise operations is compiled by LLVM into >>> much larger code than the other compilers: >>> >>> >>> http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/ED/ED37DAF5.shtml >>> >>> http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/1F/1F4003C7.shtml >>> >>> Note that this is straight-line code, so LLVM's output will run 4-5 >>> times longer than everyone else's. &g...

...hy is this interesting? Because it provides a way to systematically find areas of weakness in an optimizer, relative to a collection of other optimizers. If people would find it useful, I can put the full set of results on the web when time permits. I call the resulting codes "maximally embarrassing" since each function represents some significant failure to optimize. The global maximally embarrasing function is one where various versions of gcc (including llvm-gcc) emit code returning constant 0 and clang emits 762 bytes of x86. The C code is this: int ZZ_00005bbd(int x,int y...

Hi folks, I've posted an updated code size comparison between LLVM, GCC, and others here: http://embed.cs.utah.edu/embarrassing/ New in this version: - much larger collection of harvested functions: more than 360,000 - bug fixes and UI improvements - added the x86 Open64 compiler John

Dear R helpers, I have what another member on this forum described as an embarrassingly parallel problem. I am trying to fit models on subsets of some data based on unique combinations of two id factors in the dataset. Total number of combinations is 30^5, and this takes a long time. So, I would like fit models for each of the datasets produced by subsetting on the unique combina...

Dear list, could someone point me to the right command to subtract 2 columns in a data.frame. Might be a bit embarrassing question. But I cannot figure out how to do this simple command in R. Thanks, Ulrich -- __________________________________________________ Ulrich Leopold MSc. Department of Physical Geography Institute for Biodiversity and Ecosystem Dynamics Faculty of Science University of Amsterdam Nieuwe...

I am having trouble saving graphs. Using the Aqua interface (which is not my preferred interface), I have no problems plotting a graph, adding additional lines, points, references, etc., and then saving it to a file using, for example, the dev2bitmap command. I have found that, running R with Xemacs+ESS under X11 (which I prefer over Aqua), this is not possible. I can either send the graph to a

2009/11/22 Jon Harrop <jon at ffconsultancy.com>: > What about parallelization? I thought about that for a while, but if you keep your classes/files small, intra-unit parallelization gains are probably not worth the time invested. Compiling multiple files is embarrassingly parallel. [1] MHO is that, though inter-unit optimizations can take much longer, the benefits are worthwhile. Multiple threads/processes with a message passing interface in between them would be a start, but compiling a unix kernel that way would be tricky memory-wise. ;) cheers, --renato [...

...owing approach: 1. Install minimal system. 2. yum groupinstall "X Window System" 3. yum install gdm gnome-classic-session gnome-terminal liberation-fonts 4. Install applications as needed. This morning, the package group "X Window System" seems to have disappeared. This is embarrassing. What happened? Niki -- Microlinux - Solutions informatiques 100% Linux et logiciels libres 7, place de l'?glise - 30730 Montpezat Web : http://www.microlinux.fr Mail : info at microlinux.fr T?l. : 04 66 63 10 32

[cross-posting to the GCC and LLVM lists] I've updated the code size results here: http://embed.cs.utah.edu/embarrassing/dec_09/ The changes for this run were: - delete a number of testcases that contained use of uninitialized local variables - turn off frame pointer emission for all compilers - ask all compilers to target x86 + SSE3 - ask all compilers to not emit stack protector code - run unix2dos on the...

On Tue, Jan 26, 2010 at 7:42 PM, John Regehr <regehr at cs.utah.edu> wrote: >> Umm, can you find one that isn't a popcount implementation? > > Ok. > > MMX psadbw instruction: > > http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/CE/CE3DA132.shtml > > Position of first set bit: > > http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/1F/1F4003C7.shtml > > Log2 floor: > > http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/83/837A80E9.shtml > > Pixel forma...

...te: > 2009/11/22 Jon Harrop<jon at ffconsultancy.com>: >> What about parallelization? > > I thought about that for a while, but if you keep your classes/files > small, intra-unit parallelization gains are probably not worth the > time invested. Compiling multiple files is embarrassingly parallel. > [1] Compiling multiple files is embarrassingly parallel ... which doesn't matter if your developers are doing a build+edit cycle on a single file. I don't know about the backend, but I've thought about how to make the middle parallelized. We already have the noti...

I'm planning on releasing 6.01 next week. The list of changes (so far) are appended below. This is going to be a quick bug fix release, mainly because of the rather embarrassing bug in the 6.00 that prevents booting a Linux kernel on BIOS. The idea is to get a fixed release into everyone's hands ASAP. Thanks to everyone who has helped with debugging. --- Matt Fleming (9): efi: Export __bcopyxx_len efi: Tag symbols with __export load_linux: fallb...

...e, while it was being written to, could subsequently be opened by another client for reading. I used a DVR with chasing play as an example. Didn't seem like that difficult of a question, but maybe it isn't geeky enough for some. (Or perhaps the answer is "No" and people are too embarrassed to admit Samba can't do it.)

So it would appear that llvm-gcc and clang are both slower than gcc4 which is infamous for being slow at compiling code, and yes this is with a release build/--enable-optimizations. This seems to go against notes such as http://clang.llvm.org/features.html#performance which claim clang is signifcantly faster than gcc. Below are some times and the larger object files when compiling an i386