diff options
author | 2015-03-13 14:45:40 -0700 | |
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committer | 2015-03-13 14:45:40 -0700 | |
commit | 30e666cae7d4f8183869869a907c689ced872867 (patch) | |
tree | b33f6f767f0a2207f333a996b8eb0ad786f5bba6 /src | |
parent | ecf53c6b1b7b0a41598a448bf2020083ab1d5771 (diff) |
Creates cpu_iphone.c
So that cpu_posix.c can be left untouched for the other platforms.
Diffstat (limited to 'src')
-rw-r--r-- | src/core/support/cpu_iphone.c | 53 | ||||
-rw-r--r-- | src/core/support/cpu_posix.c | 16 |
2 files changed, 66 insertions, 3 deletions
diff --git a/src/core/support/cpu_iphone.c b/src/core/support/cpu_iphone.c new file mode 100644 index 0000000000..d412a6d7ee --- /dev/null +++ b/src/core/support/cpu_iphone.c @@ -0,0 +1,53 @@ +/* + * + * Copyright 2015, Google Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following disclaimer + * in the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Google Inc. nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + */ + +#include <grpc/support/port_platform.h> + +#ifdef GPR_CPU_IPHONE + +/* Probably 2 instead of 1, but see comment on gpr_cpu_current_cpu. */ +unsigned gpr_cpu_num_cores(void) { + return 1; +} + +/* Most code that's using this is using it to shard across work queues. So + unless profiling shows it's a problem or there appears a way to detect the + currently running CPU core, let's have it shard the default way. + Note that the interface in cpu.h lets gpr_cpu_num_cores return 0, but doing + it makes it impossible for gpr_cpu_current_cpu to satisfy its stated range, + and some code might be relying on it. */ +unsigned gpr_cpu_current_cpu(void) { + return 0; +} + +#endif /* GPR_CPU_IPHONE */ diff --git a/src/core/support/cpu_posix.c b/src/core/support/cpu_posix.c index 1844e9a622..99484e37fb 100644 --- a/src/core/support/cpu_posix.c +++ b/src/core/support/cpu_posix.c @@ -42,6 +42,8 @@ #include <grpc/support/log.h> #include <grpc/support/sync.h> +static __thread char magic_thread_local; + static int ncpus = 0; static void init_ncpus() { @@ -58,10 +60,18 @@ unsigned gpr_cpu_num_cores(void) { return ncpus; } +/* This is a cheap, but good enough, pointer hash for sharding things: */ +static size_t shard_ptr(const void *info) { + size_t x = (size_t)info; + return ((x >> 4) ^ (x >> 9) ^ (x >> 14)) % gpr_cpu_num_cores(); +} + unsigned gpr_cpu_current_cpu(void) { /* NOTE: there's no way I know to return the actual cpu index portably... - most code that's using this is using it to shard across work queues though */ - return 0; + most code that's using this is using it to shard across work queues though, + so here we use thread identity instead to achieve a similar though not + identical effect */ + return shard_ptr(&magic_thread_local); } -#endif /* GPR_CPU_LINUX */ +#endif /* GPR_CPU_POSIX */ |