Improve the coalescing of instruction cache flushes on R8000 in order

not to perform redundant work. There is no direct way to flush the
cache; rather, the kernel evicts unwanted bits from the cache by
executing a block of instructions, which is expensive.

With this diff, make build time decreases about 0.4%.

Diff from miod@

diff --git a/sys/arch/mips64/mips64/cache_tfp.c b/sys/arch/mips64/mips64/cache_tfp.c
index 50e47d5..8dbb665 100644 (file)
--- a/sys/arch/mips64/mips64/cache_tfp.c
+++ b/sys/arch/mips64/mips64/cache_tfp.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cache_tfp.c,v 1.6 2016/01/05 05:27:54 visa Exp $      */
+/*     $OpenBSD: cache_tfp.c,v 1.7 2017/06/22 14:40:20 visa Exp $      */
 
 /*
  * Copyright (c) 2012 Miodrag Vallat.
@@ -128,9 +128,11 @@ tfp_InvalidateICache(struct cpu_info *ci, vaddr_t _va, size_t _sz)
        vsize_t sz;
        void (*inval_subr)(vsize_t);
 
+       if (ci->ci_cachepending_l1i != 0)
+               return;
+
        if (_sz >= ci->ci_l1inst.size) {
-               tfp_inval_icache(ci->ci_l1inst.size);
-               ci->ci_cachepending_l1i = 0;
+               ci->ci_cachepending_l1i = 1;
        } else {
                /* extend the range to multiple of 32 bytes */
                va = _va & ~(32UL - 1);