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libitm: Optimize undo log. 

libitm/
	* local.cc (GTM_LB): Use GTM::gtm_undolog.
	(GTM::gtm_thread::drop_references_undolog): Remove.
	(GTM::gtm_thread::commit_undolog,
	GTM::gtm_thread::rollback_undolog): Move to ...
	* libitm_i.h (GTM::gtm_undolog): ...here. New.
	(GTM::gtm_undolog_entry): Remove.
	(GTM::gtm_thread): Adapt.
	* beginend.cc (GTM::gtm_thread::rollback): Adapt.
	(GTM::gtm_thread::trycommit): Adapt.
	* method-serial.cc (serial_dispatch::log): Adapt.
	* method-gl.cc (gl_wt_dispatch::pre_write): Adapt.
	(gl_wt_dispatch::store): Fix likely/unlikely.
	* containers.h (GTM::vector::resize): Add additional_capacity
	parameter and handle it.
	(GTM::vector::resize_noinline): New/adapt.
	(GTM::vector::push): New.

From-SVN: r182992
This commit is contained in:
Torvald Riegel 2012-01-08 14:13:49 +00:00 committed by Torvald Riegel
parent e478624f6c
commit 11f30bb0e4
7 changed files with 83 additions and 88 deletions
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19
libitm/ChangeLog
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@ -1,3 +1,22 @@
2012-01-08 Torvald Riegel <triegel@redhat.com>
* local.cc (GTM_LB): Use GTM::gtm_undolog.
(GTM::gtm_thread::drop_references_undolog): Remove.
(GTM::gtm_thread::commit_undolog,
GTM::gtm_thread::rollback_undolog): Move to ...
* libitm_i.h (GTM::gtm_undolog): ...here. New.
(GTM::gtm_undolog_entry): Remove.
(GTM::gtm_thread): Adapt.
* beginend.cc (GTM::gtm_thread::rollback): Adapt.
(GTM::gtm_thread::trycommit): Adapt.
* method-serial.cc (serial_dispatch::log): Adapt.
* method-gl.cc (gl_wt_dispatch::pre_write): Adapt.
(gl_wt_dispatch::store): Fix likely/unlikely.
* containers.h (GTM::vector::resize): Add additional_capacity
parameter and handle it.
(GTM::vector::resize_noinline): New/adapt.
(GTM::vector::push): New.
2012-01-06 Richard Henderson <rth@redhat.com>
* configure.tgt: Support powerpc-linux and powerpc-darwin.

6
libitm/beginend.cc
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@ -1,4 +1,4 @@
/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU Transactional Memory Library (libitm).
@ -327,7 +327,7 @@ GTM::gtm_thread::rollback (gtm_transaction_cp *cp, bool aborting)
// data. Because of the latter, we have to roll it back before any
// dispatch-specific rollback (which handles synchronization with other
// transactions).
rollback_undolog (cp ? cp->undolog_size : 0);
undolog.rollback (cp ? cp->undolog_size : 0);
// Perform dispatch-specific rollback.
abi_disp()->rollback (cp);
@ -470,7 +470,7 @@ GTM::gtm_thread::trycommit ()
// We can commit the undo log after dispatch-specific commit and after
// making the transaction inactive because we only have to reset
// gtm_thread state.
commit_undolog ();
undolog.commit ();
// Reset further transaction state.
cxa_catch_count = 0;
cxa_unthrown = NULL;

28
libitm/containers.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2011 Free Software Foundation, Inc.
/* Copyright (C) 2011, 2012 Free Software Foundation, Inc.
Contributed by Torvald Riegel <triegel@redhat.com>.
This file is part of the GNU Transactional Memory Library (libitm).
@ -70,17 +70,24 @@ class vector
}
~vector<T, alloc_separate_cl>() { if (m_capacity) free(entries); }
void resize()
void resize(size_t additional_capacity)
{
if (m_capacity >= default_resize_max)
m_capacity = m_capacity + default_resize_max;
size_t target = m_capacity + additional_capacity;
if (target > default_resize_max)
m_capacity = ((target - 1 + default_resize_max) / default_resize_max)
* default_resize_max;
else
m_capacity = m_capacity * 2;
while (m_capacity < target)
m_capacity = m_capacity * 2;
if (m_capacity < default_resize_min)
m_capacity = default_resize_min;
entries = (T*) xrealloc(entries, sizeof(T) * m_capacity, alloc_separate_cl);
}
void resize_noinline() __attribute__((noinline)) { resize(); }
void resize_noinline() __attribute__((noinline)) { resize(1); }
void resize_noinline(size_t elements) __attribute__((noinline))
{
resize(elements);
}
size_t size() const { return m_size; }
size_t capacity() const { return this->capacity; }
@ -93,6 +100,15 @@ class vector
return &entries[m_size++];
}
iterator push(size_t elements)
{
// We don't want inlining here since push() is often on the fast path.
if (unlikely(m_size + elements > m_capacity)) resize_noinline(elements);
iterator it = &entries[m_size];
m_size += elements;
return it;
}
iterator pop() {
if (likely(m_size > 0))
{

35
libitm/libitm_i.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU Transactional Memory Library (libitm).
@ -93,9 +93,6 @@ struct gtm_alloc_action
bool allocated;
};
// This type is private to local.c.
struct gtm_undolog_entry;
struct gtm_thread;
// A transaction checkpoint: data that has to saved and restored when doing
@ -121,6 +118,29 @@ struct gtm_transaction_cp
void commit(gtm_thread* tx);
};
// An undo log for writes.
struct gtm_undolog
{
vector<gtm_word> undolog;
// Log the previous value at a certain address.
// The easiest way to inline this is to just define this here.
void log(const void *ptr, size_t len)
{
size_t words = (len + sizeof(gtm_word) - 1) / sizeof(gtm_word);
gtm_word *undo = undolog.push(words + 2);
memcpy(undo, ptr, len);
undo[words] = len;
undo[words + 1] = (gtm_word) ptr;
}
void commit () { undolog.clear(); }
size_t size() const { return undolog.size(); }
// In local.cc
void rollback (size_t until_size = 0);
};
// Contains all thread-specific data required by the entire library.
// This includes all data relevant to a single transaction. Because most
// thread-specific data is about the current transaction, we also refer to
@ -148,7 +168,7 @@ struct gtm_thread
gtm_jmpbuf jb;
// Data used by local.c for the undo log for both local and shared memory.
vector<gtm_undolog_entry*> undolog;
gtm_undolog undolog;
// Data used by alloc.c for the malloc/free undo log.
aa_tree<uintptr_t, gtm_alloc_action> alloc_actions;
@ -254,11 +274,6 @@ struct gtm_thread
// In eh_cpp.cc
void revert_cpp_exceptions (gtm_transaction_cp *cp = 0);
// In local.cc
void commit_undolog (void);
void rollback_undolog (size_t until_size = 0);
void drop_references_undolog (const void *, size_t);
// In retry.cc
// Must be called outside of transactions (i.e., after rollback).
void decide_retry_strategy (gtm_restart_reason);

70
libitm/local.cc
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@ -1,4 +1,4 @@
/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU Transactional Memory Library (libitm).
@ -26,29 +26,9 @@
namespace GTM HIDDEN {
struct gtm_undolog_entry
{
void *addr;
size_t len;
char saved[];
};
void
gtm_thread::commit_undolog ()
{
size_t i, n = undolog.size();
if (n > 0)
{
for (i = 0; i < n; ++i)
free (undolog[i]);
this->undolog.clear();
}
}
void
gtm_thread::rollback_undolog (size_t until_size)
gtm_undolog::rollback (size_t until_size)
{
size_t i, n = undolog.size();
@ -56,36 +36,11 @@ gtm_thread::rollback_undolog (size_t until_size)
{
for (i = n; i-- > until_size; )
{
gtm_undolog_entry *u = *undolog.pop();
if (u)
{
memcpy (u->addr, u->saved, u->len);
free (u);
}
}
}
}
/* Forget any references to PTR in the local log. */
void
gtm_thread::drop_references_undolog (const void *ptr, size_t len)
{
size_t i, n = undolog.size();
if (n > 0)
{
for (i = n; i > 0; i--)
{
gtm_undolog_entry *u = undolog[i];
/* ?? Do we need such granularity, or can we get away with
just comparing PTR and LEN. ?? */
if ((const char *)u->addr >= (const char *)ptr
&& ((const char *)u->addr + u->len <= (const char *)ptr + len))
{
free (u);
undolog[i] = NULL;
}
void *ptr = (void *) undolog[i--];
size_t len = undolog[i];
size_t words = (len + sizeof(gtm_word) - 1) / sizeof(gtm_word);
i -= words;
__builtin_memcpy (ptr, &undolog[i], len);
}
}
}
@ -94,16 +49,7 @@ void ITM_REGPARM
GTM_LB (const void *ptr, size_t len)
{
gtm_thread *tx = gtm_thr();
gtm_undolog_entry *undo;
undo = (gtm_undolog_entry *)
xmalloc (sizeof (struct gtm_undolog_entry) + len);
undo->addr = (void *) ptr;
undo->len = len;
tx->undolog.push()[0] = undo;
memcpy (undo->saved, ptr, len);
tx->undolog.log(ptr, len);
}
} // namespace GTM

7
libitm/method-gl.cc
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@ -1,4 +1,4 @@
/* Copyright (C) 2011 Free Software Foundation, Inc.
/* Copyright (C) 2011, 2012 Free Software Foundation, Inc.
Contributed by Torvald Riegel <triegel@redhat.com>.
This file is part of the GNU Transactional Memory Library (libitm).
@ -120,8 +120,7 @@ protected:
tx->shared_state.store(gl_mg::set_locked(now), memory_order_release);
}
// TODO Ensure that this gets inlined: Use internal log interface and LTO.
GTM_LB(addr, len);
tx->undolog.log(addr, len);
}
static void validate()
@ -181,7 +180,7 @@ protected:
template <typename V> static void store(V* addr, const V value,
ls_modifier mod)
{
if (unlikely(mod != WaW))
if (likely(mod != WaW))
pre_write(addr, sizeof(V));
// FIXME We would need an atomic store here but we can't just forge an
// atomic load for nonatomic data because this might not work on all

6
libitm/method-serial.cc
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@ -1,4 +1,4 @@
/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU Transactional Memory Library (libitm).
@ -107,8 +107,8 @@ class serial_dispatch : public abi_dispatch
protected:
static void log(const void *addr, size_t len)
{
// TODO Ensure that this gets inlined: Use internal log interface and LTO.
GTM_LB(addr, len);
gtm_thread *tx = gtm_thr();
tx->undolog.log(addr, len);
}
template <typename V> static V load(const V* addr, ls_modifier mod)