Changelog: v2 - v3: - __aligned(64) -> __cacheline_aligned - Replaced in sched_clock() wmb() with barrier() v1 - v2: - Early boot timestamps are now available on all 64-bit sparc processors - New hot-patched get_tick() function. This patch set: - enables early boot timestamps on SPARC, - adds offset so we count time from zero, the same as it is done on other platforms - improves the performance by inling, hot patching, and combining loads into the same cacheline. (and few other optimizations). So, the final performance of sched_clock() is faster than now: the fewer number of loads, and all of them are coming from the same cacheline. Loads can run while we are reading tick value, and we do not do function call. Current sched_clock(): sethi %hi(0xb9b400), %g1 ldx [ %g1 + 0x250 ], %g1 ldx [ %g1 ], %g1 call %g1 nop sethi %hi(0xb9b400), %g1 ldx [ %g1 + 0x300 ], %g1 mulx %o0, %g1, %g1 rett %i7 + 8 srlx %g1, 0xa, %o0 Final sched_clock(): sethi %hi(0xb9b400), %g1 ldx [ %g1 + 0x2c8 ], %g2 ldx [ %g1 + 0x2c0 ], %g1 b 42f638 <sched_clock+0x44> rd %asr24, %i0 ... sllx %i0, 1, %i0 srlx %i0, 1, %i0 mulx %i0, %g1, %i0 srlx %i0, 0xa, %i0 rett %i7 + 8 sub %o0, %g2, %o0 Pavel Tatashin (8): sparc64: remove trailing white spaces sparc64: access tick function from variable sparc64: show time stamps from zero sparc64: optimize loads in clock_sched() sparc64: improve modularity tick options sparc64: initialize time early sparc64: add hot-patched and inlined get_tick() sparc64: optimize functions that access tick arch/sparc/include/asm/setup.h | 2 +- arch/sparc/include/asm/timer_64.h | 67 ++++++++++++++++ arch/sparc/kernel/kernel.h | 3 + arch/sparc/kernel/setup_64.c | 7 +- arch/sparc/kernel/time_64.c | 155 ++++++++++++++++++++++++------------- arch/sparc/kernel/vmlinux.lds.S | 5 + 6 files changed, 181 insertions(+), 58 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
