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2016-01-08keep compressed indexes in a low-cost formatDavid Kalnischkies
Downloading and storing are two different operations were different compression types can be preferred. For downloading we provide the choice via Acquire::CompressionTypes::Order as there is a choice to be made between download size and speed – and limited by whats available in the repository. Storage on the other hand has all compressions currently supported by apt available and to reduce runtime of tools accessing these files the compression type should be a low-cost format in terms of decompression. apt traditionally stores its indexes uncompressed on disk, but has options to keep them compressed. Now that apt downloads additional files we also deal with files which simply can't be stored uncompressed as they are just too big (like Contents for apt-file). Traditionally they are downloaded in a low-cost format (gz) as repositories do not provide other formats, but there might be even lower-cost formats and for download we could introduce higher-cost in the repositories. Downloading an entire index potentially requires recompression to another format, so an update takes potentially longer – but big files are usually updated via pdiffs which has to de- and re-compress anyhow and does it on the fly anyhow, so there is no extra time needed and in general it seems to be benefitial to invest the time in update to save time later on file access.
2016-01-08allow pdiff bootstrap from all supported compressorsDavid Kalnischkies
There is no reason to enforce that the file we start the bootstrap with is compressed with a compressor which is available online. This allows us to change the on-disk format as well as deals with repositories adding/removing support for a specific compressor.
2016-01-08ensure compression cleanup even without lists-cleanupDavid Kalnischkies
If we store files compressed in lists/ and the file switched compression formats we happened to retain the "old" format, but by default the cleanup process catched this oversight and removed the file. [The initial situation described doesn't arise as we store no files by default compressed and even with apt-file configuring Contents files, we don't really have that problem as there is just .gz files for those.] We solve this by just removing any uncompressed as well as compressed (we support) file just before we move the 'new' version of the file in.
2016-01-08use one 'store' method to rule all (de)compressorsDavid Kalnischkies
Adding a new compressor method meant adding a new method as well – even if that boilt down to just linking to our generalized decompressor with a new name. That is unneeded busywork if we can instead just call the generalized decompressor and let it figure out which compressor to use based on the filenames rather than by program name. For compatibility we ship still 'gzip', 'bzip2' and co, but they are just links to our "new" 'store' method.
2016-01-08AvailableDescriptionLanguages: Use one string for all iterationsJulian Andres Klode
Do not create strings within the loop, that creates one string per language and does more work than needed. Instead, reserve enough space at the beginning and assign the prefix, and then resize and append inside the loop. Also call exists with the string itself instead of the c_str(), this means that the lookup uses the size information in the string now and does not have to call strlen() on it.
2016-01-08pkgCacheGenerator: CurMd5.Value() cannot be emptyJulian Andres Klode
It makes no sense to check if the value is empty, as it cannot be. It will always be a hexstring of exactly 32 bytes.
2016-01-08operator==(char*, StringView) use StringView.operator==Julian Andres Klode
Use the same path for both comparisons, as the operator== path is faster than just calling compare() - it avoids any comparison if the size differs. Gbp-Dch: ignore
2016-01-08pkgCacheGenerator::hash: Do not call tolower_ascii()Julian Andres Klode
Gbp-Dch: ignore
2016-01-08pkgCacheGenerator::StoreString: Get rid of std::stringJulian Andres Klode
Instead of storing a string -> map_stringitem_t mapping, create our own data type that can point to either a normal string or a string inside the cache. This avoids the creation of any string and improves performance slightly (about 4%).
2016-01-08Replace compare() == 0 checks with this == other checksJulian Andres Klode
This improves performance, as we now can ignore unequal strings based on their length already. Gbp-Dch: ignore
2016-01-08pkgCacheGenerator: Use StringView for toStringJulian Andres Klode
This removes some minor overhead. Gbp-Dch: ignore
2016-01-08pkgCacheGenerator::StoreString: Move the string into the mapJulian Andres Klode
Moving the string is likely faster than copying it. We could probably avoid strings alltogether in the future using some more crazy code, but I have not looked at that yet. Gbp-Dch: ignore
2016-01-07StringView: rfind: pos should be end of substr, not startJulian Andres Klode
Gbp-Dch: ignore
2016-01-07StringView: pos argument default should be nposJulian Andres Klode
Gbp-Dch: ignore
2016-01-07StringView::rfind(): Call rfind() instead of find() on substJulian Andres Klode
Thanks: Niels Thykier for reporting on IRC Gbp-Dch: ignore
2016-01-07Switch performance critical code to use APT::StringViewJulian Andres Klode
This improves performance of the cache generation on my ARM platform (4x Cortex A15) by about 10% to 20% from 2.35-2.50 to 2.1 seconds.
2016-01-07Introduce internal APT::StringView classJulian Andres Klode
The class APT::StringView implements a drop-in replacement for a subset of C++17 std::string_view() features. It will be dropped at a later point and may not be used in public interfaces.
2016-01-07acquire: Allow parallelizing methods without hostsJulian Andres Klode
The maximum parallelization soft limit is the number of CPU cores * 2 on systems defining _SC_NPROCESSORS_ONLN. The hard limit in all cases is Acquire::QueueHost::Limit.
2016-01-07CopyFile: Use 64 * 1024 instead of 64000 as buffer sizeJulian Andres Klode
This is a multiple of the page size and thus results in less page faults, speeding up copying. Also, while we're at at, unify all uses of that size in a constant variable APT_BUFFER_SIZE.
2016-01-07FileFd: (native) LZ4 supportJulian Andres Klode
Implement native support for LZ4 compression, using the official lz4 library.
2016-01-03Increase APT::Cache-HashTableSize default to 50503Julian Andres Klode
This drop the hash table utilization from a high 98% to acceptable 74% on unstable, and the average bucket length from 4.6 to 1.8. This improves performance by about 5%, while increasing the size of the cache by 0.2 out of 38MB, that is 0.5%. 48481 is a nice number
2016-01-03apt-cache: stats: Show a table utilization as percentageJulian Andres Klode
Gbp-Dch: ignore
2016-01-03Change compressor costs to be 100 apartJulian Andres Klode
This will give us the freedom to insert more compressors at positions in between. Also change the cost of uncompressed to 0, as that really has no overhead, and the values do not really mean much.
2016-01-03simple_compressor: Provide some accessors for end and freeJulian Andres Klode
This makes code easier to read, and somewhat more correct. Gbp-Dch: ignore
2016-01-03simple_buffer: Allow buffer size to changeJulian Andres Klode
Gbp-Dch: ignore
2016-01-02properly parse comments in apt_preferences and deb822-style sourcesDavid Kalnischkies
apt_preferences and deb822-style sources used the specialized class pkgUserTagSection to deal with comments before/after a given stanza, but it couldn't deal with comments in the stanza at all. codesearch suggests that nobody else does and a vastely superior way of working with potentially commented files is implemented now, so we can officially discourage the use of the old incomplete hack class.
2016-01-02support comments in debian/control parsingDavid Kalnischkies
Now (55153bf94ff28a23318e79aa48242244c4d82b3c) that pkgTagFile can be told to deal with all sorts of comments we can use this mode to parse dsc (as by catch) and debian/control files properly even in the wake of multiline fields spliced with comments like Build-Depends. Closes: 806775
2016-01-02add optional support for comments in pkgTagFileDavid Kalnischkies
APT usually deals with perfectly formatted files generated automatically be other programs – and as it has to parse multiple MBs of such files it tries to be fast rather than forgiving. This was always a problem if we reused this parser for files with a deb822 syntax which are mostly written by hand however, like apt_preferences or the deb822-style sources as these can include stray newlines and more importantly comments all over the place. As a stopgap we had pkgUserTagSection which deals at least with comments before and after a given stanza, but comments in between weren't really supported and now that we support parsing debian/control for e.g. build-dep we face the full comment problem e.g. with comments inbetween multi-line fields (like Build-Depends). We can't easily deal with this on the pkgTagSection level as the interface gives access to 'raw' char-pointers for performance reasons so we would need to optionally add a buffer here on which we could remove comments to hand out pointers into this buffer instead. The interface is quite large already and supports writing stanzas as well, which does not support comments at all either. So while in future it might make sense to have a parser setup which deals with and keeps comments in this commit we opt for the simpler solution for now: We officially declare that pkgTagSection does not support comments and instead expect the caller to deal with them, which in our case is pkgTagFile: pkgTagFile is extended with an additional mode which can deal with comments by dropping them from the buffer which will later form the input of pkgTagSection. The actual implementation is slightly more complex than this sentence suggests at first on one hand to have good performance and on the other to allow jumping directly to stanzas with offsets collected in a previous run (like our cache generation does it for example).
2015-12-29Do not sync the cache fileJulian Andres Klode
Integrity is taken care of by the checksum now.
2015-12-29Add support for calculating hashes over the entire cacheJulian Andres Klode
2015-12-29pkgCacheGenerator: Allow passing down an already created cacheJulian Andres Klode
If we already have opened a cache, there is no point in having to open it again.
2015-12-29pkgTagSection::Scan: Fix read of uninitialized valueJulian Andres Klode
We ignored the boundary of the buffer we were reading in while scanning for spaces.
2015-12-29strutl.cc: Add declarations for the compat _ascii() functionsJulian Andres Klode
This shuts up gcc Gbp-Dch: ignore
2015-12-29Turn tolower_ascii() and isspace_ascii() into inline functionsJulian Andres Klode
To preserve compatibility, the new inline functions have _inline as a suffix, and a macro defines the old names to refer to the inline variants. The old functions are still preserved for binary compatibility. Also simplify the implementation of both functions.
2015-12-29Switch to DJB hashing and use prime number as table sizeJulian Andres Klode
On my testing system, consisting of unstable and experimental, this reduces the average chain from 6.5 to 4.5, and the longest chain from 17 to 15.
2015-12-28BufferedFileFdPrivate: Make InternalFlush() save against errorsJulian Andres Klode
Previously, if flush errored inside the loop, data could have already been written to the wrapped descriptor without having been removed from the buffer. Also try to work around EINTR here. A better solution might be to have the individual privates detect an interrupt and return 0 in such a case, instead of relying on errno being untouched in between the syscall and the return from InternalWrite.
2015-12-28aptconfiguration: Set default compression level to 6Julian Andres Klode
Since commit 7a68effcb904b4424b54a30e448b6f2560cd1078, the xz and lzma compressors read the level of compression they shall use. A default of -9 is too much for them, this will use 674 MB, according to the xz manual page. Level -6 on the other hand only needs 94 MB memory for compression. This causes autopkgtest failures in the test-compressed-indexes test, as not enough memory exists to proceed. Change the other compression levels to 6 as well: The gzip and bzip2 FileFd backends do not read them, and use their code's default level which is 6, so do the same for external methods.
2015-12-28BufferedWriter: flushing: Check for written < size instead of <=Julian Andres Klode
This avoids some issues with InternalWrite returning 0 because it just cannot write stuff at the moment.
2015-12-27deal with empty values properly in deb822 parserDavid Kalnischkies
Regression introduced in 8710a36a01c0cb1648926792c2ad05185535558e, but such fields are unlikely in practice as it is just as simple to not have a field at all with the same result of not having a value. Closes: 808102
2015-12-27allow repositories to forbid arch:all for specific index targetsDavid Kalnischkies
Debian has a Packages file for arch:all already, but the arch:any files contain arch:all packages as well, so downloading it would be a total waste of resources. Getting this solved is on the list of things to do, but it is also the hardest part – for index targets like Contents the situation is much easier and less server/client implementations are involved so we might not want to stall them. A repository can now declare via: No-Support-for-Architecture-all: Packages that even if an arch:all Packages exists, it shouldn't be downloaded, so that support for Contents files can be added now. See also 1dd20368486820efb6ef4476ad739e967174bec4 for the implementation of downloading arch:all index targets, which this is limiting. The field uses the name of the target from the apt configuration for simplicity and is negative by design as this field is intended to be supported/needed only for a "short" time (one or two Debian releases). While this commit theoretically supports any target, its expected to only see "Packages" as a value in reality.
2015-12-27pkgcachegen.h: Hack around unordered_map not existing before C++11Julian Andres Klode
This is for public users only, which cannot use the class at all, except for the static methods.
2015-12-27FileFd: Add a buffered writing modeJulian Andres Klode
This is somewhat experimental right now, and might not work for everyone, so it is on an opt-in basis.
2015-12-27FildFd: Introduce a Flush() function and call it from Close()Julian Andres Klode
The flush function can be used for buffered writers.
2015-12-27FileFdPrivate: Add getter and setter for fieldsJulian Andres Klode
We will soon implement a buffered writing decorator and we will need to forward attribute changes to those.
2015-12-27fileutl: simple_buffer: Add write() and full() methodsJulian Andres Klode
These can be used to implement write buffering Gbp-Dch: ignore
2015-12-27fileutl: simple_buffer: Mark accessors as constJulian Andres Klode
Suggested by David. Gbp-Dch: ignore
2015-12-27FileFdPrivate: Extract SimpleBuffer and mark it as hiddenJulian Andres Klode
Gbp-Dch: ignore
2015-12-27ParseDepends: Mark branches for build-dep parsing as unlikelyJulian Andres Klode
We do not see those branches at all during normal mode of operation (that is, during cache generation), so tell the compiler about it.
2015-12-27debListParser: Do not validate Description-md5 for correctness twiceJulian Andres Klode
The Set() method returns false if the input is no hex number, so simply use that.
2015-12-27Hex2Digit: Do not use isxdigit()Niels Thykier
We directly check if we are a hex digit in HexDigit, so use that information. [jak@debian.org: Commit message wording]