|
| From: | Paolo Bonzini |
| Subject: | Re: [Qemu-devel] [PATCH 02/10] compiler.h: add QEMU_CACHELINE + QEMU_ALIGN() + QEMU_CACHELINE_ALIGNED |
| Date: | Tue, 5 Apr 2016 17:29:05 +0200 |
| User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 05/04/2016 14:58, Peter Maydell wrote:
>> >
>> > You should make this a value taken from configure. In linux you could use
>> > something like:
>> >
>> > getconf LEVEL1_DCACHE_LINESIZE
>> >
>> > Or an equivalent program using sysconf(3) if getconf is not present.
> The cache line size at compile time is not necessarily the cache
> line size at runtime...
But the size of data structures cannot change at run-time. A bigger
worry is cross-compilation.
Linux has these defaults:
Alpha 32 or 64
ARM configurable, 64 for ARMv7
AArch64 128
PPC 128
s390 256
x86 configurable, default 64
which should be easy to copy in QEMU too.
Paolo
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