search for: compression

The simple ordinary yum update of CentOS 5.3 spits a bunch of transaction check errors regarding packages perl-IO-Compress-Zlib-2.015-1.el5.rf.noarch and perl-IO-Compress-2.020-1.el5.rf.noarch which is supposed to replace perl-IO-Compress-Base-2.015-1.el5.rf.noarch: Transaction Check Error: file /usr/lib/perl5/vendor_perl/5.8.8/IO/Compress/Adapter/Deflate.pm from install of

flight 10593 linux real [real] http://www.chiark.greenend.org.uk/~xensrcts/logs/10593/ Failures :-/ but no regressions. Tests which are failing intermittently (not blocking): test-amd64-amd64-xl-sedf 13 guest-localmigrate.2 fail pass in 10581 test-i386-i386-pv 16 guest-start.2 fail pass in 10570 test-amd64-i386-rhel6hvm-amd 7 redhat-install

Folks, I'd like to get expert's opinion on which compression level is suitable for lld's -compress-debug-section=zlib option, which let the linker compress .debug_* sections using zlib. Currently, lld uses compression level 9 which produces the smallest output in exchange for a longer link time. My question is, is this what people actually want? We didn...

flight 22084 xen-unstable real [real] http://www.chiark.greenend.org.uk/~xensrcts/logs/22084/ Failures :-/ but no regressions. Tests which did not succeed, but are not blocking: test-amd64-amd64-xl-pcipt-intel 9 guest-start fail never pass test-armhf-armhf-xl 5 xen-boot fail never pass test-amd64-i386-xend-winxpsp3 16 leak-check/check

...nded advantage for compressing the debug sections? - (i) Improved link time through smaller IO / (ii) Improved Load / startup time for the debugger / (iii) Smaller exe with debug info for distribution / disk space? For i) and ii) how much this is worth it depends on balance of storage bandwidth to compression (i) / decompression (ii) bandwidth. For spinning drives it *might* be a win but for SATA and especially PCIe / NVMe SSD it could be a CPU bottleneck? Though we should also bear in mind that compression can be pipelined with writes in i) and debug info loading could be lazy in ii) (e.g. for highly...

Hi, Is there a way in which rsync's -z compression (zlib) utility can be benchmarked? I'm trying to compare the compression ratio between rsync and external compression tools like gzip and bzip2. Are there any advantages to using rsync's internal compression mechanism specified with the -z option compared to solely applying external com...

...ace? That way users who care about the finer details can configure it themselves. And we should pick sensible options for the default. James On 2 August 2018 at 11:08, Pavel Labath via llvm-dev < llvm-dev at lists.llvm.org> wrote: > I don't claim to be an expert, but I did some zlib compression > benchmarks in the past. IIRC, my conclusion from that was that the > "DEFAULT" zlib level (6) is indeed a very good default for a lot of > cases -- it does not generate much larger outputs, while being > significantly faster than the max level. This all depends on the data &...

...distribute executables with debug info widely > I think it is at least less important than (1). Agreed. > I think (1) is definitely the case, and that's also true for a distributed build system with which a lot of object files are copied between machines. > My suggestion was to use compression level 9 when both -O2 and -compress-debug-section=zlib are specified. Ok great, I'm less concerned if it still requires an explicit -compress-debug-section=zlib even with -O2 (I thought you were proposing to add to O2) Still for informational / advisory purposes it would be good for us to pro...

Not really, as well as some sensitivity to the input data overall performance of the link with compression will depend on how this is implemented in lld - how is it parallelized? How is it chunked? Is it effectively pipelined with IO? Or, I wouldn't feel comfortable being able to make a recommendation to our end-users on whether to use this option or not based on my existing extensive benchmarking...

I''ve noticed that: - with x86-64 Fedora 15 DVD install images: - du -sh <ROOT VOLUME> was 36 GB - btrfs df | grep -i data have shown over 40 GB used - without - du -sh <ROOT VOLUME> is 34 GB - btrfs df | grep -i data have shown less then 34 GB used It seems that iso files are considered compressable while they may not be (and penalty is severe - 3x). Regards

Rsync supports the capability of compressing data before sending. So does OpenSSH. It would be probably be a waste of resources and time to enable both compression capabilities at the same time, but it is not clear to me whether, in general, it makes better sense to enable rsync compression or SSH compression. My first thought would be that SSH compression might yield better results, on the ground that SSH will try to cram as much data as possible in a chann...

Ah ah, the demo effect... just after I said I did not have much issues with repos... ^_^ A collegue installed some packages (for perconna) and since then a server insists on replacing 2 base packages with 2 rfx packages, even when I gave a lower priority to rfx... Installed: perl-IO-Compress-Base-2.020-127.el6.x86_64 Installed: 1:perl-Compress-Raw-Zlib-2.020-127.el6.x86_64 Installed:

Hello, I''m currently trying to understand how compression in btrfs works. I could not find any detailed description about it. So here are my questions. 1. How is decided what to compress and what not? After a fast test with a 2g image file, I''ve looked into the extents of that file with find-new and it turned out that only some of the first exte...

...ct. Of course, this is open to change since I just wrote down some ideas I had months ago, while researching the topic as a graduate student in Computer Science, and since I''m not an opensolaris/ZFS expert at all. I would really appreciate any suggestion or comments. PROJECT PROPOSAL: ZFS Compression Algorithms. The main purpose of this project is the development of new compression schemes for the ZFS file system. We plan to start with the development of a fast implementation of a Burrows Wheeler Transform based algorithm (BWT). BWT is an outstanding tool and the currently known lossless compr...

Why isn't the compression level added in a metadata block by the flac encoder itself (just like the encoder version)? In this way all programs that read the file can see what compression level was used. thx 2007/7/4, Scot Thompson <scot.thompson@cox.net>: > > This has been asked many times. The answer is no....

"Using FLAC binary : /Users/Marcus/flac/test/../src/flac/flac Original file size 441044 bytes. Compression level 1, file size 421393 bytes. Compression level 2, file size 421393 bytes. Compression level 3, file size 373613 bytes. Compression level 4, file size 369517 bytes. Compression level 5, file size 369517 bytes. Compression level 6, file size 369517 bytes. Compression level 7, file siz...

Hi, I just installed 2009.06 and found that compression isn''t enabled by default when filesystems are created. Does is make sense to have an RFE open for this? (I''ll open one tonight if need be.) We keep telling people to turn on compression. Are there any situations where turning on compression doesn''t make sense, like rpool/...

...ed to OpenBSD > base, and I don't know if that would be accepted. Do you have any > performance numbers for zstd in this application? A key stroke is here 10 bytes of raw data which zstd compresses usually into 10 bytes while zlib manages to squeeze it into 5 bytes. This leads to better compression ratio for zlib in ssh's accounting (visible in verbose mode after connection terminates). The data length, that will be transferred over the wire, is the same for 5 and 10 bytes data after the crypto part (with padding and so on). Regarding statistics, do you have anything specific in mind? A...

https://bugzilla.samba.org/show_bug.cgi?id=9864 Summary: Allow permanent compression of destination files Product: rsync Version: 3.1.0 Platform: All OS/Version: All Status: NEW Severity: enhancement Priority: P5 Component: core AssignedTo: wayned at samba.org ReportedBy: me at haravikk...

Hello again I have a file from SPSS in .sav format. when I run library(foreign) cvar<-as.data.frame(read.spss("c:\\NDRI\\cvar\\data\\cvar2rev3.sav")) I get a warning Warning message: c:\NDRI\cvar\data\cvar2rev3.sav: Compression bias (0) is not the usual value of 100. The data appear to be OK, but I am concerned. (I tried searching the archives and the documenation for data import export, but saw nothing). Thanks as always Peter Peter L. Flom, PhD Assistant Director, Statistics and Data Analysis Core Center for D...