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authorIan Lance Taylor <iant@google.com>2008-01-02 23:48:49 +0000
committerIan Lance Taylor <iant@google.com>2008-01-02 23:48:49 +0000
commitcb29561284eaa37c5c8967e49a5db0a4064368bf (patch)
treef4e88f9b60483aeb87c7cbfda3445f3da58edcc0 /gold/fileread.h
parent2745d86e69ec4659f39cfe0406948578f791ac4f (diff)
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Reduce the number of system calls. Use readv instead of pread. Do
better handling of cached views.
Diffstat (limited to 'gold/fileread.h')
-rw-r--r--gold/fileread.h72
1 files changed, 69 insertions, 3 deletions
diff --git a/gold/fileread.h b/gold/fileread.h
index 1c47f24..428c2f0 100644
--- a/gold/fileread.h
+++ b/gold/fileread.h
@@ -46,8 +46,9 @@ class File_read
{
public:
File_read()
- : name_(), descriptor_(-1), size_(0), token_(false), views_(),
- saved_views_(), contents_(NULL), mapped_bytes_(0), released_(true)
+ : name_(), descriptor_(-1), object_count_(0), size_(0), token_(false),
+ views_(), saved_views_(), contents_(NULL), mapped_bytes_(0),
+ released_(true)
{ }
~File_read();
@@ -68,6 +69,16 @@ class File_read
filename() const
{ return this->name_; }
+ // Add an object associated with a file.
+ void
+ add_object()
+ { ++this->object_count_; }
+
+ // Remove an object associated with a file.
+ void
+ remove_object()
+ { --this->object_count_; }
+
// Lock the file for exclusive access within a particular Task::run
// execution. This means that the descriptor can not be closed.
// This routine may only be called when the workqueue lock is held.
@@ -126,6 +137,34 @@ class File_read
File_view*
get_lasting_view(off_t start, section_size_type size, bool cache);
+ // Mark all views as no longer cached.
+ void
+ clear_view_cache_marks();
+
+ // A struct used to do a multiple read.
+ struct Read_multiple_entry
+ {
+ // The file offset of the data to read.
+ off_t file_offset;
+ // The amount of data to read.
+ section_size_type size;
+ // The buffer where the data should be placed.
+ unsigned char* buffer;
+
+ Read_multiple_entry(off_t o, section_size_type s, unsigned char* b)
+ : file_offset(o), size(s), buffer(b)
+ { }
+ };
+
+ typedef std::vector<Read_multiple_entry> Read_multiple;
+
+ // Read a bunch of data from the file into various different
+ // locations. The vector must be sorted by ascending file_offset.
+ // BASE is a base offset to be added to all the offsets in the
+ // vector.
+ void
+ read_multiple(off_t base, const Read_multiple&);
+
// Dump statistical information to stderr.
static void
print_stats();
@@ -154,7 +193,7 @@ class File_read
View(off_t start, section_size_type size, const unsigned char* data,
bool cache, bool mapped)
: start_(start), size_(size), data_(data), lock_count_(0),
- cache_(cache), mapped_(mapped)
+ cache_(cache), mapped_(mapped), accessed_(true)
{ }
~View();
@@ -184,10 +223,26 @@ class File_read
set_cache()
{ this->cache_ = true; }
+ void
+ clear_cache()
+ { this->cache_ = false; }
+
bool
should_cache() const
{ return this->cache_; }
+ void
+ set_accessed()
+ { this->accessed_ = true; }
+
+ void
+ clear_accessed()
+ { this->accessed_= false; }
+
+ bool
+ accessed() const
+ { return this->accessed_; }
+
private:
View(const View&);
View& operator=(const View&);
@@ -198,6 +253,7 @@ class File_read
int lock_count_;
bool cache_;
bool mapped_;
+ bool accessed_;
};
friend class View;
@@ -238,10 +294,20 @@ class File_read
// A simple list of Views.
typedef std::list<View*> Saved_views;
+ // The maximum number of entries we will pass to ::readv.
+ static const size_t max_readv_entries = 128;
+
+ // Use readv to read data.
+ void
+ do_readv(off_t base, const Read_multiple&, size_t start, size_t count);
+
// File name.
std::string name_;
// File descriptor.
int descriptor_;
+ // The number of objects associated with this file. This will be
+ // more than 1 in the case of an archive.
+ int object_count_;
// File size.
off_t size_;
// A token used to lock the file.