Date: Fri, 29 Oct 2010 19:26:02 +0400 From: Artemiev Igor <ai@kliksys.ru> To: freebsd-stable@freebsd.org, freebsd-fs@freebsd.org Subject: Re: 8.1-STABLE: zfs and sendfile: problem still exists Message-ID: <20101029152602.GA18613@two.kliksys.ru> In-Reply-To: <4CCADD37.7000306@icyb.net.ua> References: <3D1C350B94A44E5D95BAA1596D1EBF13@vosz.local> <20101029090417.GA17537@two.kliksys.ru> <4CCABFC2.3040701@icyb.net.ua> <4CCADD37.7000306@icyb.net.ua>
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On Fri, Oct 29, 2010 at 05:41:59PM +0300, Andriy Gapon wrote: > What svn revision of FreeBSD source tree did you test? r213936. Revision seems a little old. > Ah, I think I see what's going on. > Either sendfile should (have an option to) use VOP_GETPAGES to request data or ZFS > mappedread should use vm_grab_page instead of vm_lookup_page for UIO_NOCOPY case. > Currently ZFS would read a whole FS block into ARC, but populate only one page > with data and for the rest it would just wastefully do uiomove(UIO_NOCOPY) from > ARC data. > So, e.g. zpool iostat would show that there are only few actual reads from a pool. > The rest of the time must be spent churning over the data already in ARC and > doing page-per-VOP_READ copies from it. I can test it, but what allocflags? VM_ALLOC_RETRY|VM_ALLOC_NORMAL?
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