Summary:
IOSTATS_ADD_IF_POSITIVE() doesn't seem to a macro that aims to improve performance but does the opposite. The counter to add is almost always positive so the if is just a waste. Furthermore, adding to a thread local variable seemse to be much cheaper than an if condition if branch prediction has a possibility to be wrong. Remove the macro.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8984
Test Plan: See CI completes.
Reviewed By: anand1976
Differential Revision: D31348163
fbshipit-source-id: 30af6d45e1aa8bbc09b2c046206cce6f67f4777a
Summary:
Before this PR, `get_iostats_context()` will silently return a nullptr if no thread_local support is detected.
This can be the result of build_detect_platform's failure to compile the simple code snippet on certain platforms, as
reported in https://github.com/facebook/mysql-5.6/issues/904.
To be safe, we should fail the compilation if user does not opt out IOStatsContext and
ROCKSDB_SUPPORT_THREAD_LOCAL is not defined.
If RocksDB relies on c++11, can we just always use thread_local? It turns out there might be
performance concerns (https://github.com/facebook/rocksdb/issues/5774),
which is beyond the scope of this PR. We can revisit this later. Here, we stick to the original impl.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8117
Reviewed By: ajkr
Differential Revision: D27356847
Pulled By: riversand963
fbshipit-source-id: f7d5776842277598d8341b955febb601946801ae
Summary:
For performance purposes, the lower level routines were changed to use a SystemClock* instead of a std::shared_ptr<SystemClock>. The shared ptr has some performance degradation on certain hardware classes.
For most of the system, there is no risk of the pointer being deleted/invalid because the shared_ptr will be stored elsewhere. For example, the ImmutableDBOptions stores the Env which has a std::shared_ptr<SystemClock> in it. The SystemClock* within the ImmutableDBOptions is essentially a "short cut" to gain access to this constant resource.
There were a few classes (PeriodicWorkScheduler?) where the "short cut" property did not hold. In those cases, the shared pointer was preserved.
Using db_bench readrandom perf_level=3 on my EC2 box, this change performed as well or better than 6.17:
6.17: readrandom : 28.046 micros/op 854902 ops/sec; 61.3 MB/s (355999 of 355999 found)
6.18: readrandom : 32.615 micros/op 735306 ops/sec; 52.7 MB/s (290999 of 290999 found)
PR: readrandom : 27.500 micros/op 871909 ops/sec; 62.5 MB/s (367999 of 367999 found)
(Note that the times for 6.18 are prior to revert of the SystemClock).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8033
Reviewed By: pdillinger
Differential Revision: D27014563
Pulled By: mrambacher
fbshipit-source-id: ad0459eba03182e454391b5926bf5cdd45657b67
Summary:
This is likely a temp fix before we figure out a better way.
PerfStepTimer is used intensively in certain benchmarking/testings. https://github.com/facebook/rocksdb/issues/7858 stores a `shared_ptr` to system clock in PerfStepTimer which gets created each time a `PerfStepTimer` object is created. The atomic operations in `shared_ptr` may add overhead in CPU cycles. Therefore, we change it back to a raw `SystemClock*` for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8006
Test Plan: make check
Reviewed By: pdillinger
Differential Revision: D26703560
Pulled By: riversand963
fbshipit-source-id: 519d0769b28da2334bea7d86c848fcc26ee8a17f
Summary:
Introduces and uses a SystemClock class to RocksDB. This class contains the time-related functions of an Env and these functions can be redirected from the Env to the SystemClock.
Many of the places that used an Env (Timer, PerfStepTimer, RepeatableThread, RateLimiter, WriteController) for time-related functions have been changed to use SystemClock instead. There are likely more places that can be changed, but this is a start to show what can/should be done. Over time it would be nice to migrate most (if not all) of the uses of the time functions from the Env to the SystemClock.
There are several Env classes that implement these functions. Most of these have not been converted yet to SystemClock implementations; that will come in a subsequent PR. It would be good to unify many of the Mock Timer implementations, so that they behave similarly and be tested similarly (some override Sleep, some use a MockSleep, etc).
Additionally, this change will allow new methods to be introduced to the SystemClock (like https://github.com/facebook/rocksdb/issues/7101 WaitFor) in a consistent manner across a smaller number of classes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7858
Reviewed By: pdillinger
Differential Revision: D26006406
Pulled By: mrambacher
fbshipit-source-id: ed10a8abbdab7ff2e23d69d85bd25b3e7e899e90
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433
Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.
Differential Revision: D19977691
fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
Summary:
I think when PR https://github.com/facebook/rocksdb/pull/4889 added the `IOSTATS_CPU_TIMER_GUARD` define to this header file, the noop version in the `#else` branch was forgotten.
Not sure if this is common, but on my MacOS machine it breaks my build
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5136
Differential Revision: D14727727
Pulled By: siying
fbshipit-source-id: 1076e56bdbe6ecda01d461b371dabf7f1593a149
Summary:
Measure CPU time consumed for a compaction and report it in the stats report
Enable NowCPUNanos() to work for MacOS
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4889
Differential Revision: D13701276
Pulled By: zinoale
fbshipit-source-id: 5024e5bbccd4dd10fd90d947870237f436445055
Summary:
After 7f6c02dda1, the same get_perf_context() is called both of internally and externally. However, I found internally this is not got inlined. I don't know why this is the case, but directly referencing perf_context is the logical way to do.
Closes https://github.com/facebook/rocksdb/pull/2892
Differential Revision: D5843789
Pulled By: siying
fbshipit-source-id: b49777d8809f35847699291bb7f8ea2754c3af49
Summary:
… headers
https://github.com/facebook/rocksdb/pull/2199 should not reference RocksDB-specific macros (like ROCKSDB_SUPPORT_THREAD_LOCAL in this case) to public headers, `iostats_context.h` and `perf_context.h`. We shouldn't do that because users have to provide these compiler flags when building their binary with RocksDB.
We should hide the thread local global variable inside our implementation and just expose a function api to retrieve these variables. It may break some users for now but good for long term.
make check -j64
Closes https://github.com/facebook/rocksdb/pull/2380
Differential Revision: D5177896
Pulled By: lightmark
fbshipit-source-id: 6fcdfac57f2e2dcfe60992b7385c5403f6dcb390
Summary:
We've had a couple CockroachDB users fail to build RocksDB on exotic platforms, so I figured I'd try my hand at solving these issues upstream. The problems stem from a) `USE_SSE=1` being too aggressive about turning on SSE4.2, even on toolchains that don't support SSE4.2 and b) RocksDB attempting to detect support for thread-local storage based on OS, even though it can vary by compiler on the same OS.
See the individual commit messages for details. Regarding SSE support, this PR should change virtually nothing for non-CMake based builds. `make`, `PORTABLE=1 make`, `USE_SSE=1 make`, and `PORTABLE=1 USE_SSE=1 make` function exactly as before, except that SSE support will be automatically disabled when a simple SSE4.2-using test program fails to compile, as it does on OpenBSD. (OpenBSD's ports GCC supports SSE4.2, but its binutils do not, so `__SSE_4_2__` is defined but an SSE4.2-using program will fail to assemble.) A warning is emitted in this case. The CMake build is modified to support the same set of options, except that `USE_SSE` is spelled `FORCE_SSE42` because `USE_SSE` is rather useless now that we can automatically detect SSE support, and I figure changing options in the CMake build is less disruptive than changing the non-CMake build.
I've tested these changes on all the platforms I can get my hands on (macOS, Windows MSVC, Windows MinGW, and OpenBSD) and it all works splendidly. Let me know if there's anything you object to—I obviously don't mean to break any of your build pipelines in the process of fixing ours downstream.
Closes https://github.com/facebook/rocksdb/pull/2199
Differential Revision: D5054042
Pulled By: yiwu-arbug
fbshipit-source-id: 938e1fc665c049c02ae15698e1409155b8e72171
Summary:
Move some files under util/ to new directories env/, monitoring/ options/ and cache/
Closes https://github.com/facebook/rocksdb/pull/2090
Differential Revision: D4833681
Pulled By: siying
fbshipit-source-id: 2fd8bef
Summary: Removed two unused macros in iostats_context
Test Plan: make all check
Reviewers: sdong, rven, IslamAbdelRahman, kradhakrishnan, igor
Reviewed By: igor
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D40005
Summary:
We occasionally get write stalls (>1s Write() calls) on HDD under read load. The following timers explain almost all of the stalls:
- perf_context.db_mutex_lock_nanos
- perf_context.db_condition_wait_nanos
- iostats_context.open_time
- iostats_context.allocate_time
- iostats_context.write_time
- iostats_context.range_sync_time
- iostats_context.logger_time
In my experiments each of these occasionally takes >1s on write path under some workload. There are rare cases when Write() takes long but none of these takes long.
Test Plan: Added code to our application to write the listed timings to log for slow writes. They usually add up to almost exactly the time Write() call took.
Reviewers: rven, yhchiang, sdong
Reviewed By: sdong
Subscribers: march, dhruba, tnovak
Differential Revision: https://reviews.facebook.net/D39177
Summary: No __thread for ios.
Test Plan: compile works for ios now
Reviewers: ljin, dhruba
Reviewed By: dhruba
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D22491
Summary:
This diff allows the I/O stats about Flush and Compaction to be reported
in a more accurate way. Instead of measuring the size of a file, it
measure I/O cost in per read / write basis.
Test Plan: make all check
Reviewers: sdong, igor, ljin
Reviewed By: ljin
Subscribers: leveldb
Differential Revision: https://reviews.facebook.net/D19383
sdong