dash/src/util.h
Wladimir J. van der Laan 1f46de1973
Merge #12618: Set SCHED_BATCH priority on the loadblk thread.
d54874d Set SCHED_BATCH priority on the loadblk thread. (Evan Klitzke)

Pull request description:

  Today I came across #10271, and while reading the discussion #6358 was linked to. Linux systems have a `SCHED_BATCH` scheduler priority that is useful for threads like loadblk. You can find the full details at [sched(7)](http://man7.org/linux/man-pages/man7/sched.7.html), but I'll quote the relevant part of the man page below:

  > ...this policy will cause the scheduler to always assume that the thread is
  CPU-intensive. Consequently, the scheduler will apply a small scheduling penalty
  with respect to wakeup behavior, so that this thread is mildly disfavored in
  scheduling decisions.
  >
  > This policy is useful for workloads that are noninteractive, but do not want to
  lower their nice value, and for workloads that want a deterministic scheduling
  policy without interactivity causing extra preemptions (between the workload's
  tasks).

  I think this change is useful independently of #10271 and irrespective of whether that change is merged. Under normal operation the loadblk thread will just import `mempool.dat`. However, if Bitcoin is started with `-reindex` or `-reindex-chainstate` this thread will use a great deal of CPU while it rebuilds the chainstate database (and the block database in the case of `-reindex`). By setting `SCHED_BATCH` this thread is less likely to interfere with interactive tasks (e.g. the user's web browser, text editor, etc.).

  I'm leaving the nice value unchanged (which also affects scheduling decisions) because I think that's better set by the user. Likewise I'm not using [ioprio_set(2)](http://man7.org/linux/man-pages/man2/ioprio_set.2.html) because it can cause the thread to become completely I/O starved (and knowledgeable users can use `ionice(1)` anyway).

Tree-SHA512: ea8f7d3921ed5708948809da771345cdc33efd7ba3323e9dfec07a25bc21e8612e2676f9c178e2710c7bc437e8c9cafc5e0463613688fea5699b6e8e2fec6cff
2020-12-15 22:34:03 -06:00

332 lines
9.7 KiB
C++

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core developers
// Copyright (c) 2014-2019 The Dash Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
/**
* Server/client environment: argument handling, config file parsing,
* thread wrappers, startup time
*/
#ifndef BITCOIN_UTIL_H
#define BITCOIN_UTIL_H
#if defined(HAVE_CONFIG_H)
#include <config/dash-config.h>
#endif
#include <compat.h>
#include <fs.h>
#include <logging.h>
#include <sync.h>
#include <tinyformat.h>
#include <utiltime.h>
#include <utilmemory.h>
#include <amount.h>
#include <atomic>
#include <exception>
#include <map>
#include <set>
#include <stdint.h>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include <boost/signals2/signal.hpp>
#include <boost/thread/condition_variable.hpp> // for boost::thread_interrupted
// Debugging macros
// Uncomment the following line to enable debugging messages
// or enable on a per file basis prior to inclusion of util.h
//#define ENABLE_DASH_DEBUG
#ifdef ENABLE_DASH_DEBUG
#define DBG( x ) x
#else
#define DBG( x )
#endif
//Dash only features
extern bool fMasternodeMode;
extern bool fDisableGovernance;
extern int nWalletBackups;
// Application startup time (used for uptime calculation)
int64_t GetStartupTime();
/** Signals for translation. */
class CTranslationInterface
{
public:
/** Translate a message to the native language of the user. */
boost::signals2::signal<std::string (const char* psz)> Translate;
};
extern CTranslationInterface translationInterface;
extern const char * const BITCOIN_CONF_FILENAME;
extern const char * const BITCOIN_PID_FILENAME;
/**
* Translation function: Call Translate signal on UI interface, which returns a boost::optional result.
* If no translation slot is registered, nothing is returned, and simply return the input.
*/
inline std::string _(const char* psz)
{
boost::optional<std::string> rv = translationInterface.Translate(psz);
return rv ? (*rv) : psz;
}
void SetupEnvironment();
bool SetupNetworking();
template<typename... Args>
bool error(const char* fmt, const Args&... args)
{
LogPrintStr("ERROR: " + SafeStringFormat(fmt, args...) + "\n");
return false;
}
void PrintExceptionContinue(const std::exception_ptr pex, const char* pszExceptionOrigin);
bool FileCommit(FILE *file);
bool TruncateFile(FILE *file, unsigned int length);
int RaiseFileDescriptorLimit(int nMinFD);
void AllocateFileRange(FILE *file, unsigned int offset, unsigned int length);
bool RenameOver(fs::path src, fs::path dest);
bool LockDirectory(const fs::path& directory, const std::string lockfile_name, bool probe_only=false);
bool DirIsWritable(const fs::path& directory);
/** Release all directory locks. This is used for unit testing only, at runtime
* the global destructor will take care of the locks.
*/
void ReleaseDirectoryLocks();
bool TryCreateDirectories(const fs::path& p);
fs::path GetDefaultDataDir();
const fs::path &GetBlocksDir(bool fNetSpecific = true);
const fs::path &GetDataDir(bool fNetSpecific = true);
fs::path GetBackupsDir();
void ClearDatadirCache();
fs::path GetConfigFile(const std::string& confPath);
#ifndef WIN32
fs::path GetPidFile();
void CreatePidFile(const fs::path &path, pid_t pid);
#endif
#ifdef WIN32
fs::path GetSpecialFolderPath(int nFolder, bool fCreate = true);
#endif
void runCommand(const std::string& strCommand);
/**
* Most paths passed as configuration arguments are treated as relative to
* the datadir if they are not absolute.
*
* @param path The path to be conditionally prefixed with datadir.
* @param net_specific Forwarded to GetDataDir().
* @return The normalized path.
*/
fs::path AbsPathForConfigVal(const fs::path& path, bool net_specific = true);
inline bool IsSwitchChar(char c)
{
#ifdef WIN32
return c == '-' || c == '/';
#else
return c == '-';
#endif
}
class ArgsManager
{
protected:
friend class ArgsManagerHelper;
mutable CCriticalSection cs_args;
std::map<std::string, std::vector<std::string>> m_override_args;
std::map<std::string, std::vector<std::string>> m_config_args;
std::string m_network;
std::set<std::string> m_network_only_args;
void ReadConfigStream(std::istream& stream);
public:
ArgsManager();
/**
* Select the network in use
*/
void SelectConfigNetwork(const std::string& network);
void ParseParameters(int argc, const char*const argv[]);
void ReadConfigFile(const std::string& confPath);
/**
* Log warnings for options in m_section_only_args when
* they are specified in the default section but not overridden
* on the command line or in a network-specific section in the
* config file.
*/
void WarnForSectionOnlyArgs();
/**
* Return a vector of strings of the given argument
*
* @param strArg Argument to get (e.g. "-foo")
* @return command-line arguments
*/
std::vector<std::string> GetArgs(const std::string& strArg) const;
/**
* Return true if the given argument has been manually set
*
* @param strArg Argument to get (e.g. "-foo")
* @return true if the argument has been set
*/
bool IsArgSet(const std::string& strArg) const;
/**
* Return true if the argument was originally passed as a negated option,
* i.e. -nofoo.
*
* @param strArg Argument to get (e.g. "-foo")
* @return true if the argument was passed negated
*/
bool IsArgNegated(const std::string& strArg) const;
/**
* Return string argument or default value
*
* @param strArg Argument to get (e.g. "-foo")
* @param strDefault (e.g. "1")
* @return command-line argument or default value
*/
std::string GetArg(const std::string& strArg, const std::string& strDefault) const;
/**
* Return integer argument or default value
*
* @param strArg Argument to get (e.g. "-foo")
* @param nDefault (e.g. 1)
* @return command-line argument (0 if invalid number) or default value
*/
int64_t GetArg(const std::string& strArg, int64_t nDefault) const;
/**
* Return boolean argument or default value
*
* @param strArg Argument to get (e.g. "-foo")
* @param fDefault (true or false)
* @return command-line argument or default value
*/
bool GetBoolArg(const std::string& strArg, bool fDefault) const;
/**
* Set an argument if it doesn't already have a value
*
* @param strArg Argument to set (e.g. "-foo")
* @param strValue Value (e.g. "1")
* @return true if argument gets set, false if it already had a value
*/
bool SoftSetArg(const std::string& strArg, const std::string& strValue);
/**
* Set a boolean argument if it doesn't already have a value
*
* @param strArg Argument to set (e.g. "-foo")
* @param fValue Value (e.g. false)
* @return true if argument gets set, false if it already had a value
*/
bool SoftSetBoolArg(const std::string& strArg, bool fValue);
// Forces an arg setting. Called by SoftSetArg() if the arg hasn't already
// been set. Also called directly in testing.
void ForceSetArg(const std::string& strArg, const std::string& strValue);
void ForceRemoveArg(const std::string& strArg);
/**
* Looks for -regtest, -testnet and returns the appropriate BIP70 chain name.
* @return CBaseChainParams::MAIN by default; raises runtime error if an invalid combination is given.
*/
std::string GetChainName() const;
/**
* Looks for -devnet and returns either "devnet-<name>" or simply "devnet" if no name was specified.
* This function should never be called for non-devnets.
* @return either "devnet-<name>" or "devnet"; raises runtime error if no -devent was specified.
*/
std::string GetDevNetName() const;
};
extern ArgsManager gArgs;
/**
* Format a string to be used as group of options in help messages
*
* @param message Group name (e.g. "RPC server options:")
* @return the formatted string
*/
std::string HelpMessageGroup(const std::string& message);
/**
* Format a string to be used as option description in help messages
*
* @param option Option message (e.g. "-rpcuser=<user>")
* @param message Option description (e.g. "Username for JSON-RPC connections")
* @return the formatted string
*/
std::string HelpMessageOpt(const std::string& option, const std::string& message);
/**
* Return the number of cores available on the current system.
* @note This does count virtual cores, such as those provided by HyperThreading.
*/
int GetNumCores();
void RenameThread(const char* name);
std::string GetThreadName();
namespace ctpl {
class thread_pool;
}
void RenameThreadPool(ctpl::thread_pool& tp, const char* baseName);
/**
* .. and a wrapper that just calls func once
*/
template <typename Callable> void TraceThread(const std::string name, Callable func)
{
std::string s = "dash-" + name;
RenameThread(s.c_str());
try
{
LogPrintf("%s thread start\n", name);
func();
LogPrintf("%s thread exit\n", name);
}
catch (const boost::thread_interrupted&)
{
LogPrintf("%s thread interrupt\n", name);
throw;
}
catch (...) {
PrintExceptionContinue(std::current_exception(), name.c_str());
throw;
}
}
std::string CopyrightHolders(const std::string& strPrefix, unsigned int nStartYear, unsigned int nEndYear);
/**
* On platforms that support it, tell the kernel the calling thread is
* CPU-intensive and non-interactive. See SCHED_BATCH in sched(7) for details.
*
* @return The return value of sched_setschedule(), or 1 on systems without
* sched_setchedule().
*/
int ScheduleBatchPriority(void);
#endif // BITCOIN_UTIL_H