Date: Tue, 15 Jul 2014 10:01:37 -0400 From: John Baldwin <jhb@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Nathan Whitehorn <nwhitehorn@freebsd.org> Subject: Re: svn commit: r268624 - head/sys/dev/vt/hw/efifb Message-ID: <201407151001.38146.jhb@freebsd.org> In-Reply-To: <20140714175345.GK93733@kib.kiev.ua> References: <201407141742.s6EHgMNt094168@svn.freebsd.org> <20140714175345.GK93733@kib.kiev.ua>
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On Monday, July 14, 2014 1:53:45 pm Konstantin Belousov wrote: > On Mon, Jul 14, 2014 at 05:42:22PM +0000, Nathan Whitehorn wrote: > > Author: nwhitehorn > > Date: Mon Jul 14 17:42:22 2014 > > New Revision: 268624 > > URL: http://svnweb.freebsd.org/changeset/base/268624 > > > > Log: > > On my Lenovo laptop, the firmware maps the EFI framebuffer with MTRRs set > > to uncacheable. This leads to execrable console performance. Once PMAP is > > up, remap the framebuffer as write-combining. This reduces boot time on my > > laptop by 60% when booting with EFI. > > > > MFC after: 2 weeks > > > > Modified: > > head/sys/dev/vt/hw/efifb/efifb.c > > > > Modified: head/sys/dev/vt/hw/efifb/efifb.c > > ============================================================================== > > --- head/sys/dev/vt/hw/efifb/efifb.c Mon Jul 14 17:16:09 2014 (r268623) > > +++ head/sys/dev/vt/hw/efifb/efifb.c Mon Jul 14 17:42:22 2014 (r268624) > > @@ -53,6 +53,7 @@ __FBSDID("$FreeBSD$"); > > > > static vd_init_t vt_efifb_init; > > static vd_probe_t vt_efifb_probe; > > +static void vt_efifb_remap(void *efifb_data); > > > > static struct vt_driver vt_efifb_driver = { > > .vd_name = "efifb", > > @@ -68,6 +69,8 @@ static struct vt_driver vt_efifb_driver > > static struct fb_info local_info; > > VT_DRIVER_DECLARE(vt_efifb, vt_efifb_driver); > > > > +SYSINIT(efifb_remap, SI_SUB_KMEM, SI_ORDER_ANY, vt_efifb_remap, &local_info); > > + > > static int > > vt_efifb_probe(struct vt_device *vd) > > { > > @@ -133,9 +136,9 @@ vt_efifb_init(struct vt_device *vd) > > info->fb_size = info->fb_height * info->fb_stride; > > info->fb_pbase = efifb->fb_addr; > > /* > > - * We could use pmap_mapdev here except that the kernel pmap > > - * hasn't been created yet and hence any attempt to lock it will > > - * fail. > > + * Use the direct map as a crutch until pmap is available. Once pmap > > + * is online, the framebuffer will be remapped by vt_efifb_remap() > > + * using pmap_mapdev_attr(). > > */ > > info->fb_vbase = PHYS_TO_DMAP(efifb->fb_addr); > > > > @@ -163,3 +166,22 @@ vt_efifb_init(struct vt_device *vd) > > > > return (CN_INTERNAL); > > } > > + > > +static void > > +vt_efifb_remap(void *xinfo) > > +{ > > + struct fb_info *info = xinfo; > > + > > + if (info->fb_pbase == 0) > > + return; > > + > > + /* > > + * Remap as write-combining. This massively improves performance and > > + * happens very early in kernel initialization, when everything is > > + * still single-threaded and interrupts are off, so replacing the > > + * mapping address is safe. > > + */ > > + info->fb_vbase = (intptr_t)pmap_mapdev_attr(info->fb_pbase, > > + info->fb_size, VM_MEMATTR_WRITE_COMBINING); > > +} > > + > Could you use pmap_change_attr() ? This would save some KVA. I think that is a no-op in this case. pmap_mapdev_attr() on amd64 is already going to re-use the existing DMAP mapping after doing pmap_change_attr() on it. -- John Baldwin
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