or to put differently, the difference is disapperance of vn_stat from the codepath.
On 8/8/20, Mateusz Guzik <[email protected]> wrote: > tmpfs_getattr fills > 100 bytes worth of data into struct vattr, which > then has to be converted to struct stat format. The conversion happens > to copy some of it as it is and branch on other stuff. tmpfs_stat > elides the entire process. > > On 8/8/20, Alan Somers <[email protected]> wrote: >> On Fri, Aug 7, 2020 at 5:06 PM Mateusz Guzik <[email protected]> wrote: >> >>> Author: mjg >>> Date: Fri Aug 7 23:06:40 2020 >>> New Revision: 364044 >>> URL: https://svnweb.freebsd.org/changeset/base/364044 >>> >>> Log: >>> vfs: add VOP_STAT >>> >>> The current scheme of calling VOP_GETATTR adds avoidable overhead. >>> >>> An example with tmpfs doing fstat (ops/s): >>> before: 7488958 >>> after: 7913833 >>> >>> Reviewed by: kib (previous version) >>> Differential Revision: https://reviews.freebsd.org/D25910 >>> >>> Modified: >>> head/share/man/man9/Makefile >>> head/share/man/man9/VOP_ATTRIB.9 >>> head/sys/compat/linuxkpi/common/src/linux_compat.c >>> head/sys/kern/vfs_default.c >>> head/sys/kern/vfs_syscalls.c >>> head/sys/kern/vfs_vnops.c >>> head/sys/kern/vnode_if.src >>> head/sys/security/audit/audit_arg.c >>> head/sys/sys/vnode.h >>> >> >> What avoidable overhead? The tmpfs_stat handler that you added in your >> next >> commit looks pretty much the same as vop_getattr. I'm missing where the >> performance improvement comes from. Could you please fill me in? >> -Alan >> > > > -- > Mateusz Guzik <mjguzik gmail.com> > -- Mateusz Guzik <mjguzik gmail.com> _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
