TStorageFactoryFile Class Reference

#include <TStorageFactoryFile.h>

Inheritance diagram for TStorageFactoryFile:

Public Member Functions
	ClassDef (TStorageFactoryFile, 0)
virtual Bool_t	ReadBuffer (char *buf, Int_t len)
virtual Bool_t	ReadBuffer (char *buf, Long64_t pos, Int_t len)
virtual Bool_t	ReadBufferAsync (Long64_t off, Int_t len)
virtual Bool_t	ReadBuffers (char *buf, Long64_t *pos, Int_t *len, Int_t nbuf)
void	ResetErrno (void) const
	TStorageFactoryFile (const char *name, Option_t *option, const char *ftitle, Int_t compress, Int_t netopt, Bool_t parallelopen=kFALSE)
	TStorageFactoryFile (const char *name, Option_t *option="", const char *ftitle="", Int_t compress=1)
virtual Bool_t	WriteBuffer (const char *buf, Int_t len)
	~TStorageFactoryFile (void)

Protected Member Functions
virtual Int_t	SysClose (Int_t fd)
virtual Int_t	SysOpen (const char *pathname, Int_t flags, UInt_t mode)
virtual Long64_t	SysSeek (Int_t fd, Long64_t offset, Int_t whence)
virtual Int_t	SysStat (Int_t fd, Long_t *id, Long64_t *size, Long_t *flags, Long_t *modtime)
virtual Int_t	SysSync (Int_t fd)

Private Member Functions
void	Initialize (const char *name, Option_t *option="")
Bool_t	ReadBuffersSync (char *buf, Long64_t *pos, Int_t *len, Int_t nbuf)
	TStorageFactoryFile (void)

Private Attributes
Storage *	storage_

Detailed Description

TFile wrapper around StorageFactory and Storage.

Definition at line 14 of file TStorageFactoryFile.h.

Constructor & Destructor Documentation

TStorageFactoryFile::TStorageFactoryFile	(	const char *	name,
		Option_t *	option,
		const char *	ftitle,
		Int_t	compress,
		Int_t	netopt,
		Bool_t	parallelopen = kFALSE
	)

Definition at line 102 of file TStorageFactoryFile.cc.

References Initialize().

  : TFile(path, "NET", ftitle, compress), // Pass "NET" to prevent local access in base class
    storage_(0)
{
  Initialize(path, option);
}

TStorageFactoryFile::TStorageFactoryFile	(	const char *	name,
		Option_t *	option = "",
		const char *	ftitle = "",
		Int_t	compress = 1
	)

Definition at line 114 of file TStorageFactoryFile.cc.

References Initialize().

  : TFile(path, "NET", ftitle, compress), // Pass "NET" to prevent local access in base class
    storage_(0)
{
  Initialize(path, option);
}

TStorageFactoryFile::~TStorageFactoryFile

(

void

)

Definition at line 195 of file TStorageFactoryFile.cc.

References storage_.

{
  Close();
  delete storage_;
}

TStorageFactoryFile::TStorageFactoryFile ( void  )

private

Definition at line 91 of file TStorageFactoryFile.cc.

References s_statsCtor, storageCounter(), and StorageAccount::Stamp::tick().

  : storage_(0)
{
  StorageAccount::Stamp stats(storageCounter(s_statsCtor, "construct"));
  stats.tick(0);
}

Member Function Documentation

TStorageFactoryFile::ClassDef	(	TStorageFactoryFile	,
		0
	)

void TStorageFactoryFile::Initialize ( const char *  name, Option_t *  option = ""  )

private

Definition at line 125 of file TStorageFactoryFile.cc.

References SurfaceDeformationFactory::create(), edm::hlt::Exception, StorageFactory::get(), IOFlags::OpenCreate, IOFlags::OpenRead, IOFlags::OpenWrite, scaleCards::path, SiPixelLorentzAngle_cfi::read, s_statsCtor, storage_, storageCounter(), StorageAccount::Stamp::tick(), and update.

Referenced by TStorageFactoryFile().

{
  StorageAccount::Stamp stats(storageCounter(s_statsCtor, "construct"));

  // Enable AsyncReading.
  // This was the default for 5.27, but turned off by default for 5.32.
  // In our testing, AsyncReading is the fastest mechanism available.
  // In 5.32, the AsyncPrefetching mechanism is preferred, but has been a
  // performance hit in our "average case" tests.
  gEnv->SetValue("TFile.AsyncReading", 1);

  // Parse options; at the moment we only accept read!
  fOption = option;
  fOption.ToUpper();

  if (fOption == "NEW")
    fOption = "CREATE";

  Bool_t create   = (fOption == "CREATE");
  Bool_t recreate = (fOption == "RECREATE");
  Bool_t update   = (fOption == "UPDATE");
  Bool_t read     = (fOption == "READ");

  if (!create && !recreate && !update && !read)
  {
    read = true;
    fOption = "READ";
  }

  if (recreate)
  {
    if (!gSystem->AccessPathName(path, kFileExists))
      gSystem->Unlink(path);

    recreate = false;
    create   = true;
    fOption  = "CREATE";
  }
  assert(!recreate);

  if (update && gSystem->AccessPathName(path, kFileExists))
  {
    update = kFALSE;
    create = kTRUE;
  }

  int           openFlags = IOFlags::OpenRead;
  if (!read)    openFlags |= IOFlags::OpenWrite;
  if (create)   openFlags |= IOFlags::OpenCreate;
  //if (recreate) openFlags |= IOFlags::OpenCreate | IOFlags::OpenTruncate;

  // Open storage
  if (! (storage_ = StorageFactory::get()->open(path, openFlags)))
  {
     MakeZombie();
     gDirectory = gROOT;
     throw cms::Exception("TStorageFactoryFile::TStorageFactoryFile()")
       << "Cannot open file '" << path << "'";
  }

  fRealName = path;
  fD = 0; // sorry, meaningless
  fWritable = read ? kFALSE : kTRUE;

  Init(create);

  stats.tick(0);
}

Bool_t TStorageFactoryFile::ReadBuffer ( char *  buf, Int_t  len  )

virtual

Definition at line 215 of file TStorageFactoryFile.cc.

References trackerHits::c, n, s_statsCPrefetch, s_statsCRead, s_statsRead, s_statsXRead, storage_, storageCounter(), StorageAccount::Stamp::tick(), and IOInput::xread().

Referenced by ReadBuffer().

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("ReadBuffer", "Cannot read from a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("ReadBuffer", "Cannot read from a file that is not open");
    return kTRUE;
  }

  // Read specified byte range from the storage.  Returns kTRUE in
  // case of error.  Note that ROOT uses this function recursively
  // to fill the cache; we use a flag to make sure our accounting
  // is reflected in a comprehensible manner.  The "read" counter
  // will include both, "readc" indicates how much read from the
  // cache, "readu" indicates how much we failed to read from the
  // cache (excluding those recursive reads), and "readx" counts
  // the amount actually passed to read from the storage object.
  StorageAccount::Stamp stats(storageCounter(s_statsRead, "read"));

  // If we have a cache, read from there first.  This returns 0
  // if the block hasn't been prefetched, 1 if it was in cache,
  // and 2 if there was an error.
  if (TFileCacheRead *c = GetCacheRead())
  {
    Long64_t here = GetRelOffset();
    Bool_t   async = c->IsAsyncReading();

    StorageAccount::Stamp cstats(async
                                 ? storageCounter(s_statsCPrefetch, "readPrefetchToCache")
                                 : storageCounter(s_statsCRead, "readViaCache"));

    Int_t st = ReadBufferViaCache(async ? 0 : buf, len);

    if (st == 2) {
      return kTRUE;
    }

    if (st == 1) {
      if (async) {
        cstats.tick(len);
        Seek(here);
      } else {
        cstats.tick(len);
        stats.tick(len);
        return kFALSE;
      }
    }
  }

  // FIXME: Re-enable read-ahead if the data wasn't in cache.
  // if (! st) storage_->caching(true, -1, s_readahead);

  // A real read
  StorageAccount::Stamp xstats(storageCounter(s_statsXRead, "readActual"));
  IOSize n = storage_->xread(buf, len);
  xstats.tick(n);
  stats.tick(n);
  return n ? kFALSE : kTRUE;
}

Bool_t TStorageFactoryFile::ReadBuffer ( char *  buf, Long64_t  pos, Int_t  len  )

virtual

Definition at line 206 of file TStorageFactoryFile.cc.

References ReadBuffer().

{
  // This function needs to be optimized to minimize seeks.
  // See TFile::ReadBuffer(char *buf, Long64_t pos, Int_t len) in ROOT 5.27.06.
  Seek(pos);
  return ReadBuffer(buf, len);
}

Bool_t TStorageFactoryFile::ReadBufferAsync ( Long64_t  off, Int_t  len  )

virtual

Definition at line 282 of file TStorageFactoryFile.cc.

References StorageFactory::CACHE_HINT_APPLICATION, StorageFactory::CACHE_HINT_STORAGE, StorageFactory::cacheHint(), f, StorageFactory::get(), o2o::iov, Storage::prefetch(), s_statsARead, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("ReadBufferAsync", "Cannot read from a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("ReadBufferAsync", "Cannot read from a file that is not open");
    return kTRUE;
  }

  StorageAccount::Stamp stats(storageCounter(s_statsARead, "readAsync"));

  // If asynchronous reading is disabled, bail out now, regardless
  // whether the underlying storage supports prefetching.  If it is
  // forced on, pretend it's on, even if the storage doesn't support
  // it, as this turns off the caching in ROOT's side.
  StorageFactory *f = StorageFactory::get();

  // Verify that we never using async reads in app-only mode
  if (f->cacheHint() == StorageFactory::CACHE_HINT_APPLICATION)
    return kTRUE;

  // Let the I/O method indicate if it can do client-side prefetch.
  // If it does, then for example TTreeCache will drop its own cache
  // and will use the client-side cache of the actual I/O layer.
  // If len is zero ROOT is probing for prefetch support.
  if (len) {
    // FIXME: Synchronise caching.
    // storage_->caching(true, -1, 0);
    ;
  }

  IOPosBuffer iov(off, (void *) 0, len ? len : 4096);
  if (storage_->prefetch(&iov, 1))
  {
    stats.tick(len);
    return kFALSE;
  }

  // Always ask ROOT to use async reads in storage-only mode,
  // regardless of whether the storage system supports it.
  if (f->cacheHint() == StorageFactory::CACHE_HINT_STORAGE)
    return kFALSE;

  // Prefetching not available right now.
  return kTRUE;
}

Bool_t TStorageFactoryFile::ReadBuffers ( char *  buf, Long64_t *  pos, Int_t *  len, Int_t  nbuf  )

virtual

Definition at line 403 of file TStorageFactoryFile.cc.

References i, o2o::iov, Storage::prefetch(), ReadBuffersSync(), s_statsARead, storage_, storageCounter(), summarizeEdmComparisonLogfiles::success, StorageAccount::Stamp::tick(), and pileupDistInMC::total.

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("ReadBuffers", "Cannot read from a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("ReadBuffers", "Cannot read from a file that is not open");
    return kTRUE;
  }

  // For synchronous reads, we have special logic to optimize the I/O requests
  // from ROOT before handing it to the storage.
  if (buf)
  {
    return ReadBuffersSync(buf, pos, len, nbuf);
  }
  // For an async read, we assume the storage system is smart enough to do the
  // optimization itself.

  // Read from underlying storage.
  void* const nobuf = 0;
  Int_t total = 0;
  std::vector<IOPosBuffer> iov;
  iov.reserve(nbuf);
  for (Int_t i = 0; i < nbuf; ++i)
  {
    iov.push_back(IOPosBuffer(pos[i], nobuf, len[i]));
    total += len[i];
  }

  // Null buffer means asynchronous reads into I/O system's cache.
  bool success;
  StorageAccount::Stamp astats(storageCounter(s_statsARead, "readAsync"));
  // Synchronise low-level cache with the supposed cache in TFile.
  // storage_->caching(true, -1, 0);
  success = storage_->prefetch(&iov[0], nbuf);
  astats.tick(total);

  // If it didn't suceeed, pass down to the base class.
  return success ? kFALSE : TFile::ReadBuffers(buf, pos, len, nbuf);
}

Bool_t TStorageFactoryFile::ReadBuffersSync ( char *  buf, Long64_t *  pos, Int_t *  len, Int_t  nbuf  )

private

Most storage systems are not prepared for the onslaught of small reads that ROOT will perform, even if they implement a vectored read interface.

Typically, on the server side, the loop is unrolled and the reads are issued sequentially - giving the OS no hint that you're about to read a very close-by byte in the near future. Normally, OS read-ahead takes care of such situations; because the storage server has so many clients, and ROOT reads look random to the OS, the read-ahead becomes disabled.

Hence, this function will repack the application-layer request into an optimized storage-layer request. The resulting request to the storage layer typically has a slightly larger number of bytes, but far less individual reads.

On average, the server's disks see a smaller number of overall reads, the number of bytes transferred over the network increases modestly (around 10%), and the single application request becomes one-to-two I/O transactions. A clear win for all cases except high-latency WAN.

Definition at line 336 of file TStorageFactoryFile.cc.

References ReadRepacker::bufferUsed(), i, ReadRepacker::iov(), o2o::iov, ReadRepacker::pack(), pos, Storage::readv(), ReadRepacker::realBytesProcessed(), query::result, s_statsXRead, storage_, storageCounter(), StorageAccount::Stamp::tick(), and ReadRepacker::unpack().

Referenced by ReadBuffers().

{
  Int_t remaining = nbuf; // Number of read requests left to process.
  Int_t pack_count; // Number of read requests processed by this iteration.
    
  IOSize remaining_buffer_size=0;
  // Calculate the remaining buffer size for the ROOT-owned buffer by adding
  // the size of the various requests.
  for (Int_t i=0; i<nbuf; i++) remaining_buffer_size+=len[i];

  char     *current_buffer = buf;
  Long64_t *current_pos    = pos;
  Int_t    *current_len    = len;

  ReadRepacker repacker;

  while (remaining > 0) {

    pack_count = repacker.pack(static_cast<long long int *>(current_pos), current_len, remaining, current_buffer, remaining_buffer_size);

    int real_bytes_processed = repacker.realBytesProcessed();
    IOSize io_buffer_used = repacker.bufferUsed();

    // Issue readv, then unpack buffers.
    StorageAccount::Stamp xstats(storageCounter(s_statsXRead, "readActual"));
    std::vector<IOPosBuffer> &iov = repacker.iov();
    IOSize result = storage_->readv(&iov[0], iov.size());
    if (result != io_buffer_used) {
      return kTRUE;
    }
    xstats.tick(io_buffer_used);
    repacker.unpack(current_buffer);

    // Update the location of the unused part of the input buffer.
    remaining_buffer_size -= real_bytes_processed;
    current_buffer += real_bytes_processed;

    current_pos += pack_count;
    current_len += pack_count;
    remaining   -= pack_count; 

  }
  assert(remaining_buffer_size == 0);
  return kFALSE;
}

void TStorageFactoryFile::ResetErrno

(

void

)

const

Definition at line 599 of file TStorageFactoryFile.cc.

{
  TSystem::ResetErrno();
}

Int_t TStorageFactoryFile::SysClose ( Int_t  fd )

protectedvirtual

Definition at line 547 of file TStorageFactoryFile.cc.

References Storage::close(), s_statsClose, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsClose, "close"));

  if (storage_)
  {
    storage_->close();
    delete storage_;
    storage_ = 0;
  }

  stats.tick();
  return 0;
}

Int_t TStorageFactoryFile::SysOpen ( const char *  pathname, Int_t  flags, UInt_t  mode  )

protectedvirtual

Definition at line 514 of file TStorageFactoryFile.cc.

References Storage::close(), edm::hlt::Exception, StorageFactory::get(), O_NONBLOCK, IOFlags::OpenAppend, IOFlags::OpenCreate, IOFlags::OpenExclusive, IOFlags::OpenNonBlock, IOFlags::OpenRead, IOFlags::OpenTruncate, IOFlags::OpenWrite, s_statsOpen, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsOpen, "open"));

  if (storage_)
  {
    storage_->close();
    delete storage_;
    storage_ = 0;
  }

  int                      openFlags = IOFlags::OpenRead;
  if (flags & O_WRONLY)    openFlags = IOFlags::OpenWrite;
  else if (flags & O_RDWR) openFlags |= IOFlags::OpenWrite;
  if (flags & O_CREAT)     openFlags |= IOFlags::OpenCreate;
  if (flags & O_APPEND)    openFlags |= IOFlags::OpenAppend;
  if (flags & O_EXCL)      openFlags |= IOFlags::OpenExclusive;
  if (flags & O_TRUNC)     openFlags |= IOFlags::OpenTruncate;
  if (flags & O_NONBLOCK)  openFlags |= IOFlags::OpenNonBlock;

  if (! (storage_ = StorageFactory::get()->open(pathname, openFlags)))
  {
     MakeZombie();
     gDirectory = gROOT;
     throw cms::Exception("TStorageFactoryFile::SysOpen()")
       << "Cannot open file '" << pathname << "'";
  }

  stats.tick();
  return 0;
}

Long64_t TStorageFactoryFile::SysSeek ( Int_t  fd, Long64_t  offset, Int_t  whence  )

protectedvirtual

Definition at line 563 of file TStorageFactoryFile.cc.

References Storage::CURRENT, Storage::END, evf::evtn::offset(), Storage::position(), s_statsSeek, Storage::SET, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsSeek, "seek"));
  Storage::Relative rel = (whence == SEEK_SET ? Storage::SET
                               : whence == SEEK_CUR ? Storage::CURRENT
                               : Storage::END);

  offset = storage_->position(offset, rel);
  stats.tick();
  return offset;
}

Int_t TStorageFactoryFile::SysStat ( Int_t  fd, Long_t *  id, Long64_t *  size, Long_t *  flags, Long_t *  modtime  )

protectedvirtual

Definition at line 585 of file TStorageFactoryFile.cc.

References s_statsStat, Storage::size(), storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsStat, "stat"));
  // FIXME: Most of this is unsupported or makes no sense with Storage
  *id = ::Hash(fRealName);
  *size = storage_->size();
  *flags = 0;
  *modtime = 0;
  stats.tick();
  return 0;
}

Int_t TStorageFactoryFile::SysSync ( Int_t  fd )

protectedvirtual

Definition at line 576 of file TStorageFactoryFile.cc.

References Storage::flush(), s_statsFlush, storage_, storageCounter(), and StorageAccount::Stamp::tick().

{
  StorageAccount::Stamp stats(storageCounter(s_statsFlush, "flush"));
  storage_->flush();
  stats.tick();
  return 0;
}

Bool_t TStorageFactoryFile::WriteBuffer ( const char *  buf, Int_t  len  )

virtual

Definition at line 451 of file TStorageFactoryFile.cc.

References n, s_statsCWrite, s_statsWrite, s_statsXWrite, storage_, storageCounter(), StorageAccount::Stamp::tick(), and IOOutput::xwrite().

{
  // Check that it's valid to access this file.
  if (IsZombie())
  {
    Error("WriteBuffer", "Cannot write to a zombie file");
    return kTRUE;
  }

  if (! IsOpen())
  {
    Error("WriteBuffer", "Cannot write to a file that is not open");
    return kTRUE;
  }

  if (! fWritable)
  {
    Error("WriteBuffer", "File is not writable");
    return kTRUE;
  }

  StorageAccount::Stamp stats(storageCounter(s_statsWrite, "write"));
  StorageAccount::Stamp cstats(storageCounter(s_statsCWrite, "writeViaCache"));

  // Try first writing via a cache, and if that's not possible, directly.
  Int_t st;
  switch ((st = WriteBufferViaCache(buf, len)))
  {
  case 0:
    // Actual write.
    {
      StorageAccount::Stamp xstats(storageCounter(s_statsXWrite, "writeActual"));
      IOSize n = storage_->xwrite(buf, len);
      xstats.tick(n);
      stats.tick(n);

      // FIXME: What if it's a short write?
      return n > 0 ? kFALSE : kTRUE;
    }

  case 1:
    cstats.tick(len);
    stats.tick(len);
    return kFALSE;

  case 2:
  default:
    Error("WriteBuffer", "Error writing to cache");
    return kTRUE;
  }
}

Member Data Documentation

Storage* TStorageFactoryFile::storage_

private

Definition at line 56 of file TStorageFactoryFile.h.

Referenced by Initialize(), ReadBuffer(), ReadBufferAsync(), ReadBuffers(), ReadBuffersSync(), SysClose(), SysOpen(), SysSeek(), SysStat(), SysSync(), WriteBuffer(), and ~TStorageFactoryFile().