Messages in this thread Patch in this message | | | Subject | [PATCH] Preset lpj values when on VMware. | From | Alok Kataria <> | Date | Mon, 02 Aug 2010 16:10:37 -0700 |
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Please consider the patch below for the tip tree. Thanks !
-- When running on VMware's platform, we have seen situations where the AP's try to calibrate the lpj values and fail to get good calibration runs becasue of timing issues. As a result delays don't work correctly on all cpus. The solutions is to set preset_lpj value based on the current tsc frequency value. This is similar to what KVM does as well.
Signed-off-by: Alok N Kataria <akataria@vmware.com>
Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c =================================================================== --- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c 2010-08-02 15:43:28.000000000 -0700 +++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c 2010-08-02 15:43:37.000000000 -0700 @@ -51,7 +51,7 @@ static inline int __vmware_platform(void static unsigned long vmware_get_tsc_khz(void) { - uint64_t tsc_hz; + uint64_t tsc_hz, lpj; uint32_t eax, ebx, ecx, edx; VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); @@ -62,6 +62,13 @@ static unsigned long vmware_get_tsc_khz( printk(KERN_INFO "TSC freq read from hypervisor : %lu.%03lu MHz\n", (unsigned long) tsc_hz / 1000, (unsigned long) tsc_hz % 1000); + + if (!preset_lpj) { + lpj = ((u64)tsc_hz * 1000); + do_div(lpj, HZ); + preset_lpj = lpj; + } + return tsc_hz; }
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