mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-07-23 02:50:29 +00:00
Simplify TLS and reduce startup latency
This change simplifies the thread-local storage support code. On Windows and Mac OS X the startup latency of __enable_tls() has been reduced from 30ms to 1ms. On Windows, TLS memory accesses will now go much faster due to better self-modifying code that prevents a function call and acquires our thread information block pointer in a single instruction.
This commit is contained in:
parent
38c3fa63fe
commit
b1d9d11be1
15 changed files with 136 additions and 312 deletions
|
@ -5,10 +5,27 @@
|
|||
#if !(__ASSEMBLER__ + __LINKER__ + 0)
|
||||
COSMOPOLITAN_C_START_
|
||||
|
||||
char *__get_tls(void) libcesque nosideeffect;
|
||||
#if defined(__GNUC__) && defined(__x86_64__) && !defined(__STRICT_ANSI__)
|
||||
/**
|
||||
* Returns location of thread information block.
|
||||
*
|
||||
* This can't be used in privileged functions.
|
||||
*/
|
||||
static noasan inline char *__get_tls(void) {
|
||||
char *tib;
|
||||
asm("mov\t%%fs:0,%0" : "=r"(tib) : /* no inputs */ : "memory");
|
||||
return tib;
|
||||
}
|
||||
#endif /* GNU x86-64 */
|
||||
|
||||
#if defined(__GNUC__) && defined(__x86_64__) && !defined(__STRICT_ANSI__)
|
||||
static noasan inline char *__get_tls_inline(void) {
|
||||
/**
|
||||
* Returns location of thread information block.
|
||||
*
|
||||
* This should be favored over __get_tls() for .privileged code that
|
||||
* can't be self-modified by __enable_tls().
|
||||
*/
|
||||
static noasan inline char *__get_tls_privileged(void) {
|
||||
char *tib, *lin = (char *)0x30;
|
||||
if (IsLinux() || IsFreebsd() || IsNetbsd() || IsOpenbsd()) {
|
||||
asm("mov\t%%fs:(%1),%0" : "=a"(tib) : "r"(lin) : "memory");
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue