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| author | Mikulas Patocka <mpatocka@redhat.com> | 2017-07-11 07:44:05 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-07-16 11:05:04 +0200 |
| commit | 5f8a16156aa1b2d0223eaee9dacdfb9bc096f610 (patch) | |
| tree | c6f700537ad052e82cbcd19cea2c108ce07db9b9 /arch | |
| parent | 5771a8c08880cdca3bfb4a3fc6d309d6bba20877 (diff) | |
| download | linux-5f8a16156aa1b2d0223eaee9dacdfb9bc096f610.tar.bz2 | |
x86/cpu: Use indirect call to measure performance in init_amd_k6()
This old piece of code is supposed to measure the performance of indirect
calls to determine if the processor is buggy or not, however the compiler
optimizer turns it into a direct call.
Use the OPTIMIZER_HIDE_VAR() macro to thwart the optimization, so that a real
indirect call is generated.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1707110737530.8746@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index bb5abe8f5fd4..3b9e220621f8 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -134,6 +134,7 @@ static void init_amd_k6(struct cpuinfo_x86 *c) n = K6_BUG_LOOP; f_vide = vide; + OPTIMIZER_HIDE_VAR(f_vide); d = rdtsc(); while (n--) f_vide(); |