Date: Sun, 1 Dec 2019 01:24:52 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Mateusz Guzik <mjguzik@gmail.com> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r355227 - head/sys/fs/tmpfs Message-ID: <20191130232452.GC10580@kib.kiev.ua> In-Reply-To: <CAGudoHF2dxwm_Xytvd2qQxuS6f_KfOtjD%2Bz=%2BEtFwAkoi%2B-vPw@mail.gmail.com> References: <201911301641.xAUGfmMt029299@repo.freebsd.org> <20191130230725.GB10580@kib.kiev.ua> <CAGudoHF2dxwm_Xytvd2qQxuS6f_KfOtjD%2Bz=%2BEtFwAkoi%2B-vPw@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, Dec 01, 2019 at 12:15:06AM +0100, Mateusz Guzik wrote: > On 12/1/19, Konstantin Belousov <kostikbel@gmail.com> wrote: > > On Sat, Nov 30, 2019 at 04:41:48PM +0000, Mateusz Guzik wrote: > >> Author: mjg > >> Date: Sat Nov 30 16:41:47 2019 > >> New Revision: 355227 > >> URL: https://svnweb.freebsd.org/changeset/base/355227 > >> > >> Log: > >> tmpfs: add fast path to tmpfs_access for common case lookup > >> > >> VEXEC consists of vast majority of all calls and almost all targets > >> have > >> at least 0111. > > On what load VEXEC is the dominant access check ? > > > > Note this is called for every directory to be traversed dooring lookup, > so for instance looking up "foo/bar/baz" performs 2 VEXEC checks. So it is for directory components traversal during lookup. Does it make sense to add something similar at the start of ufs_accessx() when neither kind of ACLs is enabled for mp ? > > Sample result from buildkernel. 64 is VEXEC. > > dtrace -n 'fbt::tmpfs_access:entry { @[args[0]->a_accmode, ((struct > tmpfs_node *)args[0]->a_vp->v_data)->tn_mode & 0111] = count(); }' > dtrace: description 'fbt::tmpfs_access:entry ' matched 1 probe > > > 384 73 1 > 16512 0 2 > 128 0 68 > 384 0 877 > 4096 0 1049 > 320 73 5965 > 4096 73 32471 > 128 73 145115 > 256 73 160569 > 256 0 999827 > 64 73 32320731 > > >> > >> Modified: > >> head/sys/fs/tmpfs/tmpfs_vnops.c > >> > >> Modified: head/sys/fs/tmpfs/tmpfs_vnops.c > >> ============================================================================== > >> --- head/sys/fs/tmpfs/tmpfs_vnops.c Sat Nov 30 16:40:16 2019 (r355226) > >> +++ head/sys/fs/tmpfs/tmpfs_vnops.c Sat Nov 30 16:41:47 2019 (r355227) > >> @@ -331,6 +331,12 @@ tmpfs_access(struct vop_access_args *v) > >> > >> node = VP_TO_TMPFS_NODE(vp); > >> > >> + /* > >> + * Common case path lookup. > >> + */ > >> + if (__predict_true(accmode == VEXEC && (node->tn_mode & 0111) == 0111)) > > The 0111 must be spelled as (S_IXUSR | S_IXGRP | S_IXOTH). > > > > Ok. > > >> + return (0); > >> + > >> switch (vp->v_type) { > >> case VDIR: > >> /* FALLTHROUGH */ > > > > > -- > Mateusz Guzik <mjguzik gmail.com>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20191130232452.GC10580>