From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: VERBOSE flags Date: Tue, 20 Sep 2016 15:30:07 +0300 Message-ID: <20160920123007.GM26673@leon.nu> References: <77cd1f09-fa39-6f75-6c01-c7ef18909f30@redhat.com> <0a26585a-2e54-1c24-d212-0e2469afb8d8@redhat.com> <20160919061558.GG3273@leon.nu> <1474288178.6520.12.camel@intel.com> <20160919132518.GH3273@leon.nu> <1474292075.6520.28.camel@intel.com> <20160920105642.GI26673@leon.nu> <1474373496.12415.28.camel@intel.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="uwB7x3tnyrZQfZJI" Return-path: Content-Disposition: inline In-Reply-To: <1474373496.12415.28.camel-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Dalessandro, Dennis" Cc: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org --uwB7x3tnyrZQfZJI Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 20, 2016 at 12:11:40PM +0000, Dalessandro, Dennis wrote: > On Tue, 2016-09-20 at 13:56 +0300, Leon Romanovsky wrote: > > > Yes we do have that, which illustrates that trace points can not do > > > everything. I had hoped to deprecate that at some point. > > > Regardless, > > > sometimes you want additional code to be added or to do something > > > slightly different. You can't do that with a tracepoint. > > > > Can you elaborate more on this topic? Which limitations did you see > > in tracepoints? > > Just making up an example. Say you have a hash table. You want to dump > the items. If you iterate over it and do a trace point, yeah the actual > trace point has little to no perf impact, but you still walk the > table.=A0 > > There are situations where you need to do more for debugging than just > printing a message.=A0 Thanks > > > In regards of other discussion in KS 2016, "tracepoints and ABI > > stability warranties" [1]. Are you strict with this tracepoints ABI? > > Honestly we are not super strict about it, but do take care not to > break/remove something that could be useful. It will be interesting to > see what comes out of the discussion. Perhaps we do need to be more > strict about them going forward. I followed the discussion and it looks like that majority are against to declare tracepoints as ABI. Otherwise, you will find yourself unable to change the kernel code. > > -Denny --uwB7x3tnyrZQfZJI Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJX4SvPAAoJEORje4g2clinwJcQALjo7+62yiF8El5o39bnD+Gy IGKN+GEU0aIkLioUvHrjzSAPZc7jxxfsmzrkX9+eIAfDP/i69w2yi1s3u5NJKPeD TmjwVfCmPVjDbFZJFge1YZ3e/F30b0PRY7xkUpTPSglUUWlvehrvQJamKsScjXff LEOzuHjrkLv7oZ8aVnhnh8KXAGxKZfumomUxhrPFZU0M/RleDEYs83YC3gHJ9ME4 yi9ZO2iIkfGERATjmv7OOzrKSyXFfvm0dVBEC9lhEY2e5owmkr8RVOpI+z4NKofU 8jm0NQK5cxtoc/mT5UyVTZFY8vj1q/UCpQ+7rcrhNLHS5vjLGFldhZozJbOPlAJi EDYTW1bU09TkIpwBwH6/Zc+4/QfYy5HrFLFgKJSsjfN6V7oBvSHmMrFR9yZ539k4 0baT2IAERIk/exg/ovFe+MFxuwEQCrTtreILXP4Hdp0mjK8LnPoi9Bn8n1YAxE4j yoF2/6dAOK0IpAxwo5aD7q2LD2Cs+4iyNqJFSERbgxN2HREjD0H6w63z0XAbkQMD 5LT5dzc1Rtophj17fcZuQjO6Xr2lzLZKj4HWleT6z00T8fWeyhwYe214ueQlhM2p 3fFXuuNUOLioSOaS1Xyvl4HoOiKhBtfyp7ygeXYCk2NNHWfuAX+jmj+65xDDvtH8 LjFYI3rMKgSxA+qoUhGD =bkRh -----END PGP SIGNATURE----- --uwB7x3tnyrZQfZJI-- -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html