"
zlib's crc32_combine() is not very efficient. It is faster to re-combine
the buffer using crc32(). It's still substantial amount of work which
could be avoided.
This patch introduces a fast implementation of crc32_combine() which
uses a different algorithm than zlib. It also utilizes intrinsics for
carry-less multiplication instruction to perform the computation faster.
The details of the algorithm can be found in code comments.
Performance results using perf_checksum and second buffer of length 64 KiB:
zlib CRC32 combine: 38'851 ns
libdeflate CRC32: 4'797 ns
fast_crc32_combine(): 11 ns
So the new implementation is 3500x faster than zlib's, and 417x faster than
re-checksumming the buffer using libdeflate.
Tested on i7-5960X CPU @ 3.00GHz
Performance was also evaluated using sstable writer benchmark:
perf_fast_forward --populate --sstable-format=mc --data-directory /tmp/perf-mc \
--value-size=10000 --rows 1000000 --datasets small-part
It yielded 9% improvement in median frag/s (129'055 vs 117'977).
Refs #3874
"
* tag 'fast-crc32-combine-v2' of github.com:tgrabiec/scylla:
tests: perf_checksum: Test fast_crc32_combine()
tests: Rename libdeflate_test to checksum_utils_test
tests: libdeflate: Add more tests for checksum_combine()
tests: libdeflate: Check both libdeflate and default checksummers
sstables: Use fast_crc_combine() in the default checksummer
utils/gz: Add fast implementation of crc32_combine()
utils/gz: Add pre-computed polynomials
utils/gz: Import Barett reduction implementation from libdeflate
utils: Extract clmul() from crc.hh
(cherry picked from commit b098b5b987)
"
One part of the improvement comes from replacing zlib's CRC32 with the one
from libdeflate, which is optimized for modern architecture and utilizes the
PCLMUL instruction.
perf_checksum test was introduced to measure performance of various
checksumming operations.
Results for 514 B (relevant for writing with compression enabled):
test iterations median mad min max
crc_test.perf_deflate_crc32_combine 58414 16.711us 3.483ns 16.708us 16.725us
crc_test.perf_adler_combine 165788278 6.059ns 0.031ns 6.027ns 7.519ns
crc_test.perf_zlib_crc32_combine 59546 16.767us 26.191ns 16.741us 16.801us
---
crc_test.perf_deflate_crc32_checksum 12705072 83.267ns 4.580ns 78.687ns 98.964ns
crc_test.perf_adler_checksum 3918014 206.701ns 23.469ns 183.231ns 258.859ns
crc_test.perf_zlib_crc32_checksum 2329682 428.787ns 0.085ns 428.702ns 510.085ns
Results for 64 KB (relevant for writing with compression disabled):
test iterations median mad min max
crc_test.perf_deflate_crc32_combine 25364 38.393us 17.683ns 38.375us 38.545us
crc_test.perf_adler_combine 169797143 5.842ns 0.009ns 5.833ns 6.901ns
crc_test.perf_zlib_crc32_combine 26067 38.663us 95.094ns 38.546us 40.523us
---
crc_test.perf_deflate_crc32_checksum 202821 4.937us 14.426ns 4.912us 5.093us
crc_test.perf_adler_checksum 44684 22.733us 206.263ns 22.492us 25.258us
crc_test.perf_zlib_crc32_checksum 18839 53.049us 36.117ns 53.013us 53.274us
The new CRC32 implementation (deflate_crc32) doesn't provide a fast
checksum_combine() yet, it delegates to zlib so it's as slow as the latter.
Because for CRC32 checksum_combine() is several orders of magnitude slower
than checksum(), we avoid calling checksum_combine() completely for this
checksummer. We still do it for adler32, which has combine() which is faster
than checksum().
SStable write performance was evaluated by running:
perf_fast_forward --populate --data-directory /tmp/perf-mc \
--rows=10000000 -c1 -m4G --datasets small-part
Below is a summary of the average frag/s for a memtable flush. Each result is
an average of about 20 flushes with stddev of about 4k.
Before:
[1] MC,lz4: 330'903
[2] LA,lz4: 450'157
[3] MC,checksum: 419'716
[4] LA,checksum: 459'559
After:
[1'] MC,lz4: 446'917 ([1] + 35%)
[2'] LA,lz4: 456'046 ([2] + 1.3%)
[3'] MC,checksum: 462'894 ([3] + 10%)
[4'] LA,checksum: 467'508 ([4] + 1.7%)
After this series, the performance of the MC format writer is similar to that
of the LA format before the series.
There seems to be a small but consistent improvement for LA too. I'm not sure
why.
"
* tag 'improve-mc-sstable-checksum-libdeflate-v3' of github.com:tgrabiec/scylla:
tests: perf: Introduce perf_checksum
tests: Add test for libdeflate CRC32 implementation
sstables: compress: Use libdeflate for crc32
sstables: compress: Rename crc32_utils to zlib_crc32_checksummer
licenses: Add libdeflate license
Integrate libdeflate with the build system
Add libdeflate submodule
sstables: Avoid checksum_combine() for the crc32 checksummer
sstables: compress: Avoid unnecessary checksum_combine()
sstables: checksum_utils: Add missing include
(cherry picked from commit 5e759b0c07)
"
This series adds proper handling of filtering queries with LIMIT.
Previously the limit was erroneously applied before filtering,
which leads to truncated results.
To avoid that, paged filtering queries now use an enhanced pager,
which remembers how many rows dropped and uses that information
to fetch for more pages if the limit is not yet reached.
For unpaged filtering queries, paging is done internally as in case
of aggregations to avoid returning keeping huge results in memory.
Also, previously, all limited queries used the page size counted
from max(page size, limit). It's not good for filtering,
because with LIMIT 1 we would then query for rows one-by-one.
To avoid that, filtered queries ask for the whole page and the results
are truncated if need be afterwards.
Tests: unit (release)
"
* 'fix_filtering_with_limit_2' of https://github.com/psarna/scylla:
tests: add filtering with LIMIT test
tests: split filtering tests from cql_query_test
cql3: add proper handling of filtering with LIMIT
service/pager: use dropped_rows to adjust how many rows to read
service/pager: virtualize max_rows_to_fetch function
cql3: add counting dropped rows in filtering pager
(cherry picked from commit 1afda28cf3)
When test.py is run with --jenkins flag Boost UTF is asked to generate
an XML file with the test results. This automatically disables the
human-readable output printed to stdout. There is no real reason to do
so and it is actually less confusing when the Boost UTF messages are in
the test output together with Scylla logger messages.
Message-Id: <20180704172913.23462-1-pdziepak@scylladb.com>
As each test completes, report it. This prevents a long-running
test in the beginning of the list from stalling output.
Message-Id: <20180526173517.23078-1-avi@scylladb.com>
"
Pass sstable version to parse, write and describe_type methods to make it possible to handle different versions.
For now serialization header from 3.x format is ignored.
Tests: units (release)
"
* 'haaawk/sstables3/loading_v4' of ssh://github.com/scylladb/seastar-dev:
Add test for loading the whole sstable
Add test for loading statistics
Add support for 3_x stats metadata
Pass sstable version to describe_type
Pass sstable version to write methods
metadata_type: add Serialization type
Pass sstable_version_types to parse methods
Add test for reading filter
Add test for read_summary
sstables 3.x: Add test for reading TOC
sstable: Make component_map version dependent
sstable::component_type: add operator<<
Extract sstable::component_type to separete header
Remove unused sstable::get_shared_components
sstable_version_types: add mc version
I forgot that I also need to update test.py for the new test.
It's unfortunate that this script doesn't pick up the list of
tests automatically (perhaps with a black-list of tests we don't
want to run). I wonder if there are additional tests we are
forgetting to run.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20180424085911.29732-1-nyh@scylladb.com>
This patch introduces view_complex_test and adds more test coverage
for materialized views.
A new file was introduced to avoid making view_schema_test slower.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
"
Enhance continuous_data_consumer to use existing vint serialization for reading
variant integers from SSTables.
Also available at:
https://github.com/scylladb/seastar-dev/commits/haaawk/sstables3/unsigned-vint-v6
Tests: units (release)
"
* 'haaawk/sstables3/unsigned-vint-v6' of ssh://github.com/scylladb/seastar-dev:
sstables: add test for continuous_data_consumer::read_unsigned_vint
buffer_input_stream: make it possible to specify chunk size
Add tests for make_limiting_data_source
Introduce make_limiting_data_source
sstables: add continuous_data_consumer::read_unsigned_vint
Cover serialized_size_from_first_byte in tests
core: add unsigned_vint::serialized_size_from_first_byte
sstables: add all dependant headers to consumer.hh
sstables: add all dependant headers to exceptions.hh
core: add #pragma once to vint-serialization.hh
Some tests escaped the --overprovisioned flag, causing them to
compete over cpu 0. Add the flag to all tests.
Message-Id: <20180410181606.8341-1-avi@scylladb.com>
This is a separate file from view_schema_test because that one is
already becoming too long to run; also, having multiple test files
means they can be executed in parallel.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
* Don't dump output of failed tests immediately, print the output
for failed tests in the end instead.
* Fix exception printing in run_test(): don't assume passed in error
object is a `bytes` (or bytes-like) object, call the object's str
operator instead and let callers encode bytes objects instead.
* Don't assume Exception object has an `out` member, use operator str
instead to convert it to string.
* Don't print progress in run_test() directly because it results in
incomprehensible output as the executors race to print to stdout. Leave
progress report to the caller who can serialize progress prints.
* Automatically detect non-tty stdout and don't try to edit already
printed text.
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <7bb7e0003ded9b28710250bff851ea849bb99f7d.1522062795.git.bdenes@scylladb.com>
By using the overprovisioned flag, we reduce polling and pinning, so
less CPU time is wasted and the scheduler has more options to schedule
reactor threads.
Now that we have a minimum boost version, we don't need to check whether
boost requires "--" before test-specific command line arguments. Removing
the check speeds up the test a little.
Specifically for the reader-permit based eviction. This test lives in a
separate executable as it uses with_cql_test_env() and thus needs a
main() of it's own.
These are quick-running tests for verifying the accepted forms of CQL
statements (and fragments) related to access-control: users, roles, and
permissions.
Establishing the allowed forms of statements is helpful for reference,
but also makes syntax changes (like those expected in later patches)
clearer and more safe.
"
Adds extension points to schema/sstables to enable hooking in
stuff, like, say, something that modifies how sstable disk io
works. (Cough, cough, *encryption*)
Extensions are processed as property keywords in CQL. To add
an extension, a "module" must register it into the extensions
object on boot time. To avoid globals (and yet don't),
extensions are reachable from config (and thus from db).
Table/view tables already contain an extension element, so
we utilize this to persist config.
schema_tables tables/views from mutations now require a "context"
object (currently only extensions, but abstracted for easier
further changes.
Because of how schemas currently operate, there is a super
lame workaround to allow "schema_registry" access to config
and by extension extensions. DB, upon instansiation, calls
a thread local global "init" in schema_registry and registers
the config. It, in turn, can then call table_from_mutations
as required.
Includes the (modified) patch to encapsulate compression
into objects, mainly because it is nice to encapsulate, and
isolate a little.
"
* 'calle/extensions-v5' of github.com:scylladb/seastar-dev:
extensions: Small unit test
sstables: Process extensions on file open
sstables::types: Add optional extensions attribute to scylla metadata
sstables::disk_types: Add hash and comparator(sstring) to disk_string
schema_tables: Load/save extensions table
cql: Add schema extensions processing to properties
schema_tables: Require context object in schema load path
schema_tables: Add opaque context object
config_file_impl: Remove ostream operators
main/init: Formalize configurables + add extensions to init call
db::config: Add extensions as a config sub-object
db::extensions: Configuration object to store various extensions
cql3::statements::property_definitions: Use std::variant instead of any
sstables: Add extension type for wrapping file io
schema: Add opaque type to represent extensions
sstables::compress/compress: Make compression a virtual object
"The motivation is that it's no longer needed after new resharding
algorithm that is the sole responsible for working with shared
sstables and regular compaction will not work with those!
So resharding will schedule deletion of shared sstables once it's
certain that shards that own them have the new unshared sstables.
The manager was needed for orchestrating deletion of shared sstable
across shards. It brings extra complexity that's not longer needed,
and it was also overloading shard 0, but the latter could have
been fixed.
Tests:
- unit: release mode
- dtest: resharding_test.py"
* 'remove_atomic_deletion_manager_v2' of github.com:raphaelsc/scylla:
Remove SSTable's atomic deletion manager
Stop using SSTable's atomic deletion manager
database: split column_family::rebuild_sstable_list
