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Introduce pthread_condattr_setclock()

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This is one of the few POSIX APIs that was missing. It lets you choose a
monotonic clock for your condition variables. This might improve perf on
some platforms. It might also grant more flexibility with NTP configs. I
know Qt is one project that believes it needs this. To introduce this, I
needed to change some the *NSYNC APIs, to support passing a clock param.
There's also new benchmarks, demonstrating Cosmopolitan's supremacy over
many libc implementations when it comes to mutex performance. Cygwin has
an alarmingly bad pthread_mutex_t implementation. It is so bad that they
would have been significantly better off if they'd used naive spinlocks.
This commit is contained in:
Justine Tunney 2024-09-02 23:37:50 -07:00
parent 79516bf08e
commit 3c61a541bd
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GPG key ID: BE714B4575D6E328
55 changed files with 449 additions and 155 deletions
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3
libc/sysv/consts.sh
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@ -577,10 +577,11 @@ syscon clock CLOCK_REALTIME_PRECISE 0 0 0 0 9 0 0 0 #
syscon clock CLOCK_REALTIME_FAST 0 0 0 0 10 0 0 0 #
syscon clock CLOCK_REALTIME_COARSE 5 5 0 0 10 0 0 2 # Linux 2.6.32+; bsd consensus; not available on RHEL5
syscon clock CLOCK_MONOTONIC 1 1 6 6 4 3 3 1 # XNU/NT faked; could move backwards if NTP introduces negative leap second
syscon clock CLOCK_MONOTONIC_RAW 4 4 4 4 4 3 3 1 # actually monotonic; not subject to NTP adjustments; Linux 2.6.28+; XNU/NT/FreeBSD/OpenBSD faked; not available on RHEL5 (will fallback to CLOCK_MONOTONIC)
syscon clock CLOCK_MONOTONIC_RAW_APPROX 4 4 5 5 4 3 3 1 # goes faster on xnu, otherwise faked
syscon clock CLOCK_MONOTONIC_PRECISE 1 1 6 6 11 3 3 1 #
syscon clock CLOCK_MONOTONIC_FAST 1 1 6 6 12 3 3 1 #
syscon clock CLOCK_MONOTONIC_COARSE 6 6 5 5 12 3 3 1 # Linux 2.6.32+; bsd consensus; not available on RHEL5
syscon clock CLOCK_MONOTONIC_RAW 4 4 4 4 127 127 127 127 # actually monotonic; not subject to NTP adjustments; Linux 2.6.28+; XNU/NT/FreeBSD/OpenBSD faked; not available on RHEL5
syscon clock CLOCK_PROCESS_CPUTIME_ID 2 2 12 12 15 2 0x40000000 4 # NetBSD lets you bitwise a PID into clockid_t
syscon clock CLOCK_THREAD_CPUTIME_ID 3 3 16 16 14 4 0x20000000 5 #
syscon clock CLOCK_PROF 127 127 127 127 2 127 2 127 #

2
libc/sysv/consts/CLOCK_MONOTONIC_RAW.S
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@ -1,2 +1,2 @@
#include "libc/sysv/consts/syscon.internal.h"
.syscon clock,CLOCK_MONOTONIC_RAW,4,4,4,4,127,127,127,127
.syscon clock,CLOCK_MONOTONIC_RAW,4,4,4,4,4,3,3,1

2
libc/sysv/consts/CLOCK_MONOTONIC_RAW_APPROX.S Normal file
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@ -0,0 +1,2 @@
#include "libc/sysv/consts/syscon.internal.h"
.syscon clock,CLOCK_MONOTONIC_RAW_APPROX,4,4,5,5,4,3,3,1

19
libc/sysv/consts/clock.h
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@ -8,7 +8,8 @@ extern const int CLOCK_MONOTONIC;
extern const int CLOCK_MONOTONIC_COARSE;
extern const int CLOCK_MONOTONIC_FAST;
extern const int CLOCK_MONOTONIC_PRECISE;
extern const int CLOCK_MONOTONIC_RAW;
extern int CLOCK_MONOTONIC_RAW;
extern int CLOCK_MONOTONIC_RAW_APPROX;
extern const int CLOCK_PROCESS_CPUTIME_ID;
extern const int CLOCK_PROF;
extern const int CLOCK_REALTIME_ALARM;
@ -24,9 +25,19 @@ extern const int CLOCK_UPTIME_PRECISE;
COSMOPOLITAN_C_END_
#define CLOCK_REALTIME 0
#define CLOCK_MONOTONIC CLOCK_MONOTONIC
#define CLOCK_PROCESS_CPUTIME_ID CLOCK_PROCESS_CPUTIME_ID
#define CLOCK_REALTIME 0
#define CLOCK_REALTIME_FAST CLOCK_REALTIME_FAST
#define CLOCK_REALTIME_PRECISE CLOCK_REALTIME_PRECISE
#define CLOCK_REALTIME_COARSE CLOCK_REALTIME_COARSE
#define CLOCK_MONOTONIC CLOCK_MONOTONIC
#define CLOCK_MONOTONIC_RAW CLOCK_MONOTONIC_RAW
#define CLOCK_MONOTONIC_RAW_APPROX CLOCK_MONOTONIC_RAW_APPROX
#define CLOCK_MONOTONIC_FAST CLOCK_MONOTONIC_FAST
#define CLOCK_MONOTONIC_PRECISE CLOCK_MONOTONIC_PRECISE
#define CLOCK_MONOTONIC_COARSE CLOCK_MONOTONIC_COARSE
#define CLOCK_THREAD_CPUTIME_ID CLOCK_THREAD_CPUTIME_ID
#define CLOCK_PROCESS_CPUTIME_ID CLOCK_PROCESS_CPUTIME_ID
#endif /* COSMOPOLITAN_LIBC_SYSV_CONSTS_CLOCK_H_ */