camerin
/
eden
mirror of https://git.eden-emu.dev/eden-emu/eden.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

super align + nosync opts

This commit is contained in:
lizzie 2025-12-06 23:51:50 +00:00 committed by crueter
parent 629dc72de7
commit 254dccf6e7
1 changed files with 48 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
src/common/fs/file.cpp
View File

@ -13,6 +13,7 @@
#include "common/fs/fs_android.h"
#endif
#include "common/logging/log.h"
#include "common/literals.h"
#ifdef _WIN32
#include <io.h>
@ -273,18 +274,59 @@ void IOFile::Open(const fs::path& path, FileAccessMode mode, FileType type, File
} else {
file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
}
#elif defined(__unix__) && !defined(__HAIKU__) && !defined(__managarm__)
#elif defined(__HAIKU__) || defined(__managarm__) || defined(__OPENORBIS__)
file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
#else
if (type == FileType::BinaryFile && mode == FileAccessMode::Read) {
struct stat st;
mmap_fd = open(path.c_str(), O_RDONLY);
fstat(mmap_fd, &st);
mmap_size = st.st_size;
mmap_base = (u8*)mmap(nullptr, mmap_size, PROT_READ, MAP_PRIVATE, mmap_fd, 0);
} else {
int map_flags = MAP_PRIVATE;
#ifdef MAP_PREFAULT_READ
// Prefaults reads so the final resulting pagetable from this big stupid mmap()
// isn't comically lazily loaded, we just coalesce everything in-place for our
// lovely mmap flags; if we didn't prefault the reads the page table will be
// constructed in-place (i.e on a read-by-read basis) causing lovely soft-faults
// which would nuke any performance gains.
//
// This of course incurs a cost in the initial mmap(2) call, but that is fine.
map_flags |= MAP_PREFAULT_READ;
#endif
#ifdef MAP_NOSYNC
// This causes physical media to not be synched to our file/memory
// This means that if the read-only file is written to, we won't see changes
// or we may see changes which are just funnily scattered, in any case
// this presumes the files won't be changed during execution
//
// Do not ever use this on write files (if we ever support that); this will create
// a fun amount of fragmentation on the disk.
map_flags |= MAP_NOSYNC;
#endif
#ifdef MAP_ALIGNED_SUPER
// File must be big enough that it's worth to super align. We can't just super-align every
// file otherwise we will run out of alignments for actually important files :)
// System doesn't guarantee a super alignment, but if it's available it will delete
// about 3 layers(?) of the TLB tree for each read/write.
// Again the cost of faults may make this negligible gains, but hey, we gotta work
// what we gotta work with.
using namespace Common::Literals;
u64 big_file_threshold = 512_MiB;
map_flags |= u64(st.st_size) >= big_file_threshold ? MAP_ALIGNED_SUPER : 0;
#endif
mmap_base = (u8*)mmap(nullptr, mmap_size, PROT_READ, map_flags, mmap_fd, 0);
if (mmap_base == MAP_FAILED) {
close(mmap_fd);
mmap_fd = -1;
} else {
posix_madvise(mmap_base, mmap_size, POSIX_MADV_WILLNEED);
}
}
// mmap(2) failed or simply we can't use it
if (mmap_fd == -1) {
file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
}
#else
file = std::fopen(path.c_str(), AccessModeToStr(mode, type));
#endif
if (!IsOpen()) {
const auto ec = std::error_code{errno, std::generic_category()};
@ -340,11 +382,7 @@ bool IOFile::Flush() const {
#endif
if (file) {
errno = 0;
#ifdef _WIN32
const auto flush_result = std::fflush(file) == 0;
#else
const auto flush_result = std::fflush(file) == 0;
#endif
auto const flush_result = std::fflush(file) == 0;
if (!flush_result) {
const auto ec = std::error_code{errno, std::generic_category()};
LOG_ERROR(Common_Filesystem, "Failed to flush the file at path={}, ec_message={}",