Date: Thu, 6 Dec 2018 04:36:02 +0000 (UTC) From: Justin Hibbits <jhibbits@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r341617 - head/sys/powerpc/powerpc Message-ID: <201812060436.wB64a2UF050154@repo.freebsd.org>
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Author: jhibbits Date: Thu Dec 6 04:36:02 2018 New Revision: 341617 URL: https://svnweb.freebsd.org/changeset/base/341617 Log: powerpc: Set very low priority mode while waiting for AP unleash event The POWER9 does not recognize 'or 27,27,27' as a thread priority NOP. On earlier POWER architectures, this NOP would note to the processor to give up resources if able, to improve performance of other threads. All processors that support the thread priority NOPs recognize the 'or 31,31,31' NOP as very low priority, so use this to perform a similar function, and not burn cycles on POWER9. Modified: head/sys/powerpc/powerpc/mp_machdep.c Modified: head/sys/powerpc/powerpc/mp_machdep.c ============================================================================== --- head/sys/powerpc/powerpc/mp_machdep.c Thu Dec 6 04:30:24 2018 (r341616) +++ head/sys/powerpc/powerpc/mp_machdep.c Thu Dec 6 04:36:02 2018 (r341617) @@ -78,7 +78,7 @@ machdep_ap_bootstrap(void) __asm __volatile("msync; isync"); while (ap_letgo == 0) - __asm __volatile("or 27,27,27"); + __asm __volatile("or 31,31,31"); __asm __volatile("or 6,6,6"); /*
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