Date: Sat, 31 Oct 1998 16:16:51 -0800 From: Mike Smith <mike@smith.net.au> To: Peter Wemm <peter@netplex.com.au> Cc: Peter Jeremy <peter.jeremy@auss2.alcatel.com.au>, hackers@FreeBSD.ORG, gallatin@cs.duke.edu Subject: Re: sync writes with softupdates enabled Message-ID: <199811010016.QAA01547@dingo.cdrom.com> In-Reply-To: Your message of "Sat, 31 Oct 1998 15:46:39 %2B0800." <199810310746.PAA18872@spinner.netplex.com.au>
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Now that this has been committed, can we have some feedback from people using mmap heavily on -current? This should make an enormous difference to mmap's performance there if it's a real fix... Andrew, how does this affect that nasty machine-pegging test program you showed me a while back? > > That's almost certainly correct. Try running without mmap. It used to > > be faster that way; maybe it is again? > > > Hmm, from vm_object.c: > > void > vm_object_page_clean(object, start, end, flags) > > pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : > 0; > pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; > VOP_FSYNC(vp, NULL, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc); > > vm_object.h: > #define OBJPC_SYNC 0x1 /* sync I/O */ > #define OBJPC_INVAL 0x2 /* invalidate */ > > Yet, we have: > > vfs_subr.c: vm_object_page_clean(vp->v_object, 0, 0, TRUE); > vfs_syscalls.c: vm_object_page_clean(vp->v_object, 0, 0, FALSE); > > param.h:#define TRUE 1 > param.h:#define FALSE 0 > > The sync_fsync() writes are calling vfs_msync() with MNT_NOWAIT, but > vfs_msync() is turning dirty mmap pages into sync writes. This behavior > is needed prior to unmount (obviously) but doesn't seem useful for the > periodic sync. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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