search for: compression

Displaying 20 results from an estimated 5608 matches for "compression".

2009 Jul 15
3
Conflicting perl packages?
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
2018 Aug 02
3
Default compression level for -compress-debug-info=zlib?
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...
2013 Nov 22
0
[xen-unstable test] 22084: tolerable FAIL - PUSHED
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
2018 Aug 02
2
Default compression level for -compress-debug-info=zlib?
...or 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...
2018 Aug 02
2
Default compression level for -compress-debug-info=zlib?
...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 &...
2018 Aug 02
3
Default compression level for -compress-debug-info=zlib?
...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...
2018 Aug 02
3
Default compression level for -compress-debug-info=zlib?
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...
2011 Sep 18
5
Inefficient storing of ISO images with compress=lzo
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
2019 Jun 25
5
About rsync over SSH and compression
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...
2013 Jan 28
2
Not respected repo priorities...
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:
2007 Jul 05
17
ZFS Compression algorithms - Project Proposal
...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...
2009 Jun 15
33
compression at zfs filesystem creation
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&...
2020 Sep 08
2
[PATCH 0/5] ZSTD compression support for OpenSSH
...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...
2010 Sep 16
2
problem reading Matlab file into R
Hi, I'm trying to read a .mat file into R (2.11.1) with medium success so far. The file I have is a MATLAB 5.0 MAT-file exported from RiverSurveyor LIVE software (http://www.sontek.com/software.php). I have R.matlab and Rcompression installed and readMat() starts reading the file, as can be seen in verbose mode (hence medium success), but then gives the following error: Error in dim(matrix) <- dimensionsArray$dim : dims [product 1] do not match the length of object [0] I put the whole verbose output at the end of this...
2012 Jun 15
6
[PATCH] Btrfs: add "nocompress" mount option
...rfs if we mount with "compress" we have no way to disable compressing by remounting (mount -o remount /mnt/btrfs), only by unmounting and mounting without "compress". This patch adds "nocompress" mount option which can be used to remount the filesystem without compression: # mount -o remount,nocompress /mnt/btrfs This option is usefull in cases when we have a filesystem mounted with "compress" and we want to disable compression but we don''t want to umount and mount it. Signed-off-by: Andrei Popa <ierdnah@gmail.com> --- fs/btrfs...
2017 Jun 10
2
Changing the name of a compressed file
Thanks for that Aki. Follow-up question. I tried to initiate compression by adding mail_plugins = $mail_plugins zlib plugin { zlib_save_level = 6 zlib_save = xz } to dovecot.conf. I restarted dovecot and sent one message to the server, and one message from the server. Neither was compressed. I changed the save type to zlib_save = bz2 and repeated. T...
2016 Dec 09
2
Re: [PATCH v3 2/6] v2v: ova: don't detect compressed disks, read the OVF instead
...ut_ova.ml > @@ -275,6 +275,13 @@ object > | None -> error (f_"no href in ovf:File (id=%s)") file_ref > | Some s -> s in > > + let expr = sprintf "/ovf:Envelope/ovf:References/ovf:File[@ovf:id='%s']/@ovf:compression" file_ref in > + let compressed = > + match xpath_string expr with > + | None | Some "identity" -> false > + | Some "gzip" -> true > + | Some s -> error (f_"unsupported compression in OVF: %s&...
2020 Jul 14
0
[PATCH v4 13/75] x86/boot/compressed/64: Rename kaslr_64.c to ident_map_64.c
From: Joerg Roedel <jroedel at suse.de> The file contains only code related to identity mapped page-tables. Rename the file and compile it always in. Signed-off-by: Joerg Roedel <jroedel at suse.de> --- arch/x86/boot/compressed/Makefile | 2 +- arch/x86/boot/compressed/{kaslr_64.c => ident_map_64.c} | 9 +++++++++
2010 Feb 06
3
mdbox compression
I was wondering if I should add compression support to mdbox one mail at a time or one file (~2MB) at a time. The tradeoffs are: * one mail at a time allows quickly seeking to wanted mail inside the file, but it can't compress mails as well * one file at a time compresses better, but seeking is slow because it can only be done by unco...
2019 Jun 25
2
About rsync over SSH and compression
Thanks; I did not think of that. I have just run a few basic tests with both rsync and OpenSSH in their default settings, when it comes to compression. SSH compression seems to have a very slight edge. However, I surmise that, given the number of knobs available on both sides (OpenSSH, in particular) one can tinker with settings almost endlessly in either side, probably being able to end up with specific situations where one or the other would be...