99c19e6a8f
vgetcyc() is full of barriers, so fetching values out of the vvar page before vgetcyc() for use after vgetcyc() results in poor code generation. Put vgetcyc() first to avoid this problem. Also, pull the tv_sec division into the loop and put all the ts writes together. The old code wrote ts->tv_sec on each iteration before the syscall fallback check and then added in the offset afterwards, which forced the compiler to pointlessly copy base->sec to ts->tv_sec on each iteration. The new version seems to generate sensible code. Saves several cycles. With this patch applied, the result is faster than before the clock_gettime() rewrite. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/3c05644d010b72216aa286a6d20b5078d5fae5cd.1538762487.git.luto@kernel.org |
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| .. | ||
| vdso32 | ||
| .gitignore | ||
| checkundef.sh | ||
| Makefile | ||
| vclock_gettime.c | ||
| vdso2c.c | ||
| vdso2c.h | ||
| vdso32-setup.c | ||
| vdso-layout.lds.S | ||
| vdso-note.S | ||
| vdso.lds.S | ||
| vdsox32.lds.S | ||
| vgetcpu.c | ||
| vma.c | ||