Date: Fri, 6 Jun 2014 18:16:19 -0700 From: Adrian Chadd <adrian@freebsd.org> To: Robert Watson <rwatson@freebsd.org>, Pawel Jakub Dawidek <pjd@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: Seeing ENOTCAPABLE from write FDs in kqueue? Message-ID: <CAJ-VmommTpKOzntUbCj6=YjL5PLu03-Yfx49QdKPrB%2BsMVFsKg@mail.gmail.com> In-Reply-To: <CAJ-VmonJaqg=WV0eTxknOQr51E5qdhDU=MdoCywz-hwZ57jj6w@mail.gmail.com>
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ping? -a On 2 June 2014 10:58, Adrian Chadd <adrian@freebsd.org> wrote: > Hi guys/all, > > I've been tinkering with my RSS stuff where I have multiple listen > sockets, one per worker thread, all terminating high throughput TCP > transactions. It's all HTTP; I'm using libevent, evhttp and a very > small amount of glue code to achieve this. > > libevent craps out from time to time because occasionally one of the > events in kqueue returns ENOTCAPABLE. > > ENOTCAPABLE: ident=1686, filter=-2, flags=0x00004000, fflags=0x00000000, data=93 > > ENOTCAPABLE: ident=1324, filter=-2, flags=0x00004000, fflags=0x00000000, data=93 > > ENOTCAPABLE: ident=1740, filter=-2, flags=0x00004000, fflags=0x00000000, data=93 > > ENOTCAPABLE: ident=1628, filter=-2, flags=0x00004000, fflags=0x00000000, data=93 > > ENOTCAPABLE: ident=1199, filter=-2, flags=0x00004000, fflags=0x00000000, data=93 > > ENOTCAPABLE: ident=818, filter=-2, flags=0x00004000, fflags=0x00000000, data=93 > > ENOTCAPABLE: ident=389, filter=-2, flags=0x00004000, fflags=0x00000000, data=93 > > It's happening on the various data FDs; not on the listen socket. > > What I'm seeing from ktrace: > > 27770 rss-http CAP operation requires <CAP_EVENT>, descriptor holds > <CAP_MAC_GET,CAP_MAC_SET,CAP_SEM_GETVALUE,CAP_SEM_POST,CAP_SEM_WAIT,CAP_EVENT,CAP_KQUEUE_EVENT,CAP_IOCTL,CAP_TTYHOOK,CAP_PDGETPID,CAP_PDWAIT,CAP_PDKILL,CAP_EXTATTR_DELETE,CAP_EXTATTR_GET,CAP_EXTATTR_LIST,CAP_EXTATTR_SET,CAP_ACL_CHECK,CAP_ACL_DELETE,CAP_ACL_GET,CAP_ACL_SET,CAP_KQUEUE_CHANGE> > > 27770 rss-http CAP operation requires <CAP_EVENT>, descriptor holds <> > > 27770 rss-http CAP operation requires <CAP_EVENT>, descriptor holds <> > > 27770 rss-http CAP operation requires <CAP_EVENT>, descriptor holds <> > > 27770 rss-http CAP operation requires <CAP_EVENT>, descriptor holds <> > > 27770 rss-http CAP operation requires <CAP_EVENT>, descriptor holds <> > > .. so, why exactly would I be seeing this? Is this some capability > race where we have an FD setup but no capability yet assigned when > it's added into the kqueue set? > > It's happening under high throughput (> 30,000 TCP sessions a second.) > > Where would I continue debugging this? > > Thanks! > > > -ahome | help
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