Date: Mon, 17 Oct 2005 23:10:31 +0000 (UTC) From: David Xu <davidxu@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/amd64/amd64 cpu_switch.S machdep.c Message-ID: <200510172310.j9HNAVPL013057@repoman.freebsd.org>
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davidxu 2005-10-17 23:10:31 UTC
FreeBSD src repository
Modified files:
sys/amd64/amd64 cpu_switch.S machdep.c
Log:
Micro optimization for context switch. Eliminate code for saving gs.base
and fs.base. We always update pcb.pcb_gsbase and pcb.pcb_fsbase
when user wants to set them, in context switch routine, we only need to
write them into registers, we never have to read them out from registers
when thread is switched away. Since rdmsr is a serialization instruction,
micro benchmark shows it is worthy to do.
Reviewed by: peter, jhb
Revision Changes Path
1.154 +0 -15 src/sys/amd64/amd64/cpu_switch.S
1.642 +2 -0 src/sys/amd64/amd64/machdep.c
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