XrdBuffManager Class Reference

#include <XrdBuffer.hh>

Collaboration diagram for XrdBuffManager:

Public Member Functions
	XrdBuffManager (int minrst=20 *60)
	~XrdBuffManager ()
void	Init ()
int	MaxSize ()
XrdBuffer *	Obtain (int bsz)
int	Recalc (int bsz)
void	Release (XrdBuffer *bp)
void	Reshape ()
void	Set (int maxmem=-1, int minw=-1)
int	Stats (char *buff, int blen, int do_sync=0)

Detailed Description

Definition at line 71 of file XrdBuffer.hh.

Constructor & Destructor Documentation

XrdBuffManager()

XrdBuffManager::XrdBuffManager

(

int

minrst = 20*60

)

Definition at line 78 of file XrdBuffer.cc.

                                         :
                   slots(XRD_BUCKETS),
                   shift(XRD_BUSHIFT),
                   pagsz(getpagesize()),
                   maxsz(1<<(XRD_BUSHIFT+XRD_BUCKETS-1)),
                   Reshaper(0, "buff reshaper")
{
 
// Clear everything to zero
//
   totbuf   = 0;
   totreq   = 0;
   totalo   = 0;
   totadj   = 0;
#ifdef _SC_PHYS_PAGES
   maxalo   = static_cast<long long>(pagsz)/8
              * static_cast<long long>(sysconf(_SC_PHYS_PAGES));
#else
   maxalo = 0x7ffffff;
#endif
   rsinprog = 0;
   minrsw   = minrst;
   memset(static_cast<void *>(bucket), 0, sizeof(bucket));
}

References XRD_BUCKETS, and XRD_BUSHIFT.

~XrdBuffManager()

XrdBuffManager::~XrdBuffManager

(

)

Definition at line 107 of file XrdBuffer.cc.

{
   XrdBuffer *bP;
 
   for (int i = 0; i < XRD_BUCKETS; i++)
       {while((bP = bucket[i].bnext))
             {bucket[i].bnext = bP->next;
              delete bP;
             }
        bucket[i].numbuf = 0;
       }
}

References XRD_BUCKETS.

Member Function Documentation

Init()

void XrdBuffManager::Init

(

)

Definition at line 124 of file XrdBuffer.cc.

{
   pthread_t tid;
   int rc;
 
// Start the reshaper thread
//
   if ((rc = XrdSysThread::Run(&tid, XrdReshaper, static_cast<void *>(this), 0,
                          "Buffer Manager reshaper")))
      Log.Emsg("BuffManager", rc, "create reshaper thread");
}

References XrdSysError::Emsg(), XrdGlobal::Log, XrdSysThread::Run(), and XrdReshaper().

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MaxSize()

int XrdBuffManager::MaxSize ( )

inline

Definition at line 83 of file XrdBuffer.hh.

{return maxsz;}

Referenced by XrdXrootdProtocol::Configure().

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Obtain()

XrdBuffer * XrdBuffManager::Obtain

(

int

bsz

)

Definition at line 140 of file XrdBuffer.cc.

{
   XrdBuffer *bp;
   char *memp;
   int mk, pk, bindex;
 
// Make sure the request is within our limits
//
   if (sz <= 0)     return 0;
   if (sz >  maxsz) return xlBuff.Obtain(sz);
 
// Calculate bucket index
//
   mk = sz >> shift;
   bindex = XrdOucUtils::Log2(mk);
   mk = minBuffSz << bindex;
   if (mk < sz) {bindex++; mk = mk << 1;}
   if (bindex >= slots) return 0;    // Should never happen!
 
// Obtain a lock on the bucket array and try to give away an existing buffer
//
    Reshaper.Lock();
    totreq++;
    bucket[bindex].numreq++;
    if ((bp = bucket[bindex].bnext))
       {bucket[bindex].bnext = bp->next; bucket[bindex].numbuf--;}
    Reshaper.UnLock();
 
// Check if we really allocated a buffer
//
   if (bp) return bp;
 
// Allocate a chunk of aligned memory
//
   pk = (mk < pagsz ? mk : pagsz);
   if (posix_memalign((void **)&memp, pk, mk)) return 0;
 
// Wrap the memory with a buffer object
//
   if (!(bp = new XrdBuffer(memp, mk, bindex))) {free(memp); return 0;}
 
// Update statistics
//
    Reshaper.Lock();
    totbuf++;
    if ((totalo += mk) > maxalo && !rsinprog)
       {rsinprog = 1; Reshaper.Signal();}
    Reshaper.UnLock();
    return bp;
}

References XrdBuffer::XrdBuffer(), XrdOucUtils::Log2(), XrdBuffXL::Obtain(), and XrdGlobal::xlBuff.

Referenced by XrdXrootdAioBuff::Alloc(), XrdXrootdAioPgrw::Alloc(), XrdHttpProtocol::Match(), XrdXrootdProtocol::Process(), and XrdXrootdProtocol::Swap().

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Recalc()

int XrdBuffManager::Recalc

(

int

bsz

)

Definition at line 195 of file XrdBuffer.cc.

{
   int mk, bindex;
 
// Make sure the request is within our limits
//
   if (sz <= 0)     return 0;
   if (sz >  maxsz) return xlBuff.Recalc(sz);
 
// Calculate bucket index
//
   mk = sz >> shift;
   bindex = XrdOucUtils::Log2(mk);
   mk = minBuffSz << bindex;
   if (mk < sz) {bindex++; mk = mk << 1;}
   if (bindex >= slots) return 0;    // Should never happen!
 
// All done, return the actual size we would have allocated
//
   return mk;
}

References XrdOucUtils::Log2(), XrdBuffXL::Recalc(), and XrdGlobal::xlBuff.

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Release()

void XrdBuffManager::Release

(

XrdBuffer *

bp

)

Definition at line 221 of file XrdBuffer.cc.

{
   int bindex = bp->bindex;
 
// Check if we should release this via the big buffer object
//
   if (bindex >= slots) {xlBuff.Release(bp); return;}
 
// Obtain a lock on the bucket array and reclaim the buffer
//
    Reshaper.Lock();
    bp->next = bucket[bp->bindex].bnext;
    bucket[bp->bindex].bnext = bp;
    bucket[bindex].numbuf++;
    Reshaper.UnLock();
}

References XrdBuffXL::Release(), and XrdGlobal::xlBuff.

Referenced by XrdXrootdAioPgrw::~XrdXrootdAioPgrw(), XrdXrootdProtocol::Process(), XrdXrootdProtocol::Reclaim(), and XrdXrootdAioBuff::Recycle().

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Reshape()

void XrdBuffManager::Reshape

(

)

Definition at line 242 of file XrdBuffer.cc.

{
int i, bufprof[XRD_BUCKETS], numfreed;
time_t delta, lastshape = time(0);
long long memslot, memhave, memtarget = (long long)(.80*(float)maxalo);
XrdSysTimer Timer;
float requests, buffers;
XrdBuffer *bp;
 
// This is an endless loop to periodically reshape the buffer pool
//
while(1)
     {Reshaper.Lock();
      while(Reshaper.Wait(minrsw) && totalo <= maxalo)
           {TRACE(MEM, "Reshaper has " <<(totalo>>10) <<"K; target " <<(memtarget>>10) <<"K");}
      if ((delta = (time(0) - lastshape)) < minrsw) 
         {Reshaper.UnLock();
          Timer.Wait((minrsw-delta)*1000);
          Reshaper.Lock();
         }
 
      // We have the lock so compute the request profile
      //
      if (totreq > slots)
         {requests = (float)totreq;
          buffers  = (float)totbuf;
          for (i = 0; i < slots; i++)
              {bufprof[i] = (int)(buffers*(((float)bucket[i].numreq)/requests));
               bucket[i].numreq = 0;
              }
          totreq = 0; memhave = totalo;
         } else memhave = 0;
      Reshaper.UnLock();
 
      // Reshape the buffer pool to agree with the request profile
      //
      memslot = maxsz; numfreed = 0;
      for (i = slots-1; i >= 0 && memhave > memtarget; i--)
          {Reshaper.Lock();
           while(bucket[i].numbuf > bufprof[i])
                if ((bp = bucket[i].bnext))
                   {bucket[i].bnext = bp->next;
                    delete bp;
                    bucket[i].numbuf--; numfreed++;
                    memhave -= memslot; totalo  -= memslot;
                    totbuf--;
                   } else {bucket[i].numbuf = 0; break;}
           Reshaper.UnLock();
           memslot = memslot>>1;
          }
 
       // All done
       //
       totadj += numfreed;
       TRACE(MEM, "Pool reshaped; " <<numfreed <<" freed; have " <<(memhave>>10) <<"K; target " <<(memtarget>>10) <<"K");
       lastshape = time(0);
       rsinprog = 0;    // No need to lock, we're the only ones now setting it
 
       xlBuff.Trim();   // Trim big buffers
      }
}

References TRACE, XrdBuffXL::Trim(), XrdSysTimer::Wait(), XrdGlobal::xlBuff, and XRD_BUCKETS.

Referenced by XrdReshaper().

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Set()

void XrdBuffManager::Set	(	int	maxmem = -1,
		int	minw = -1 )

Definition at line 308 of file XrdBuffer.cc.

{
 
// Obtain a lock and set the values
//
   Reshaper.Lock();
   if (maxmem > 0) maxalo = (long long)maxmem;
   if (minw   > 0) minrsw = minw;
   Reshaper.UnLock();
}

Stats()

int XrdBuffManager::Stats	(	char *	buff,
		int	blen,
		int	do_sync = 0 )

Definition at line 323 of file XrdBuffer.cc.

{
    static const char statfmt[] = "<stats id=\"buff\"><reqs>%d</reqs>"
                "<mem>%lld</mem><buffs>%d</buffs><adj>%d</adj>%s</stats>";
    char xlStats[1024];
    int nlen;
 
// If only size wanted, return it
//
   if (!buff) return sizeof(statfmt) + 16*4 + xlBuff.Stats(0,0);
 
// Return formatted stats
//
   if (do_sync) Reshaper.Lock();
   xlBuff.Stats(xlStats, sizeof(xlStats), do_sync);
   nlen = snprintf(buff,blen,statfmt,totreq,totalo,totbuf,totadj,xlStats);
   if (do_sync) Reshaper.UnLock();
   return nlen;
}

References XrdBuffXL::Stats(), and XrdGlobal::xlBuff.

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The documentation for this class was generated from the following files:

• XrdBuffer.hh
• XrdBuffer.cc