From 89f185fe8a036b0fabce30b20c480cf1c832bdd7 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Thu, 26 Jun 2014 11:54:39 -0400 Subject: all: remove 'extern register M *m' from runtime MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The runtime has historically held two dedicated values g (current goroutine) and m (current thread) in 'extern register' slots (TLS on x86, real registers backed by TLS on ARM). This CL removes the extern register m; code now uses g->m. On ARM, this frees up the register that formerly held m (R9). This is important for NaCl, because NaCl ARM code cannot use R9 at all. The Go 1 macrobenchmarks (those with per-op times >= 10 µs) are unaffected: BenchmarkBinaryTree17 5491374955 5471024381 -0.37% BenchmarkFannkuch11 4357101311 4275174828 -1.88% BenchmarkGobDecode 11029957 11364184 +3.03% BenchmarkGobEncode 6852205 6784822 -0.98% BenchmarkGzip 650795967 650152275 -0.10% BenchmarkGunzip 140962363 141041670 +0.06% BenchmarkHTTPClientServer 71581 73081 +2.10% BenchmarkJSONEncode 31928079 31913356 -0.05% BenchmarkJSONDecode 117470065 113689916 -3.22% BenchmarkMandelbrot200 6008923 5998712 -0.17% BenchmarkGoParse 6310917 6327487 +0.26% BenchmarkRegexpMatchMedium_1K 114568 114763 +0.17% BenchmarkRegexpMatchHard_1K 168977 169244 +0.16% BenchmarkRevcomp 935294971 914060918 -2.27% BenchmarkTemplate 145917123 148186096 +1.55% Minux previous reported larger variations, but these were caused by run-to-run noise, not repeatable slowdowns. Actual code changes by Minux. I only did the docs and the benchmarking. LGTM=dvyukov, iant, minux R=minux, josharian, iant, dave, bradfitz, dvyukov CC=golang-codereviews https://golang.org/cl/109050043 --- src/pkg/runtime/runtime.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/pkg/runtime/runtime.c') diff --git a/src/pkg/runtime/runtime.c b/src/pkg/runtime/runtime.c index 3a4f7199ed..26dbbbd3e2 100644 --- a/src/pkg/runtime/runtime.c +++ b/src/pkg/runtime/runtime.c @@ -32,8 +32,8 @@ runtime·gotraceback(bool *crash) if(crash != nil) *crash = false; - if(m->traceback != 0) - return m->traceback; + if(g->m->traceback != 0) + return g->m->traceback; x = runtime·atomicload(&traceback_cache); if(x == ~(uint32)0) { p = runtime·getenv("GOTRACEBACK"); @@ -286,11 +286,11 @@ runtime·fastrand1(void) { uint32 x; - x = m->fastrand; + x = g->m->fastrand; x += x; if(x & 0x80000000L) x ^= 0x88888eefUL; - m->fastrand = x; + g->m->fastrand = x; return x; } -- cgit v1.3-5-g9baa