Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 16 Oct 2002 14:10:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 16 Oct 2002 14:10:08 -0400 Received: from mtao-m02.ehs.aol.com ([64.12.52.8]:39124 "EHLO mtao-m02.ehs.aol.com") by vger.kernel.org with ESMTP id ; Wed, 16 Oct 2002 14:10:05 -0400 Date: Wed, 16 Oct 2002 11:15:50 -0700 From: John Gardiner Myers Subject: Re: [PATCH] async poll for 2.5 To: Davide Libenzi Cc: Benjamin LaHaise , Dan Kegel , Shailabh Nagar , linux-kernel , linux-aio , Andrew Morton , David Miller , Linus Torvalds , Stephen Tweedie Message-id: <3DADACD6.4000200@netscape.com> MIME-version: 1.0 Content-type: multipart/signed; boundary=------------ms020009010909010508050409; micalg=sha1; protocol="application/x-pkcs7-signature" X-Accept-Language: en-us, en User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.2a) Gecko/20020910 References: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6616 Lines: 129 This is a cryptographically signed message in MIME format. --------------ms020009010909010508050409 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Davide Libenzi wrote: >I knew you were going there, aka you do not understand how edge triggered >API have to be used. > Nonsense. >Even if the API will drop an event at registration >time you still cannot use this code scheme : > >int my_io(...) { > > if (event_wait(...)) > do_io(...); > >} > >You CAN NOT. And look, it is not an API problem, it's your problem that >you want to use the API like a poll()-like API. > You have insufficient basis upon which to claim I would write code as broken as above. >This because you have to consume the I/O space to push the level to 0 so >that a transaction 0->1 can happen and you can happily receive your >events. > > Of course you have to consume the I/O space to push the level to 0. What do you think I am, stupid? This is done with something like: for (;;) { fd = event_wait(...); while (do_io(fd) != EAGAIN); } Trying to do at once as much work as one can on a given fd helps keep that fd's context information in cache. If one needs to have the fd yield the CPU in order to reduce system latency, one generates a user-mode event. --------------ms020009010909010508050409 Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIK7TCC A4UwggLuoAMCAQICAlvfMA0GCSqGSIb3DQEBBAUAMIGTMQswCQYDVQQGEwJVUzELMAkGA1UE CBMCQ0ExFjAUBgNVBAcTDU1vdW50YWluIFZpZXcxGzAZBgNVBAoTEkFtZXJpY2EgT25saW5l IEluYzEZMBcGA1UECxMQQU9MIFRlY2hub2xvZ2llczEnMCUGA1UEAxMeSW50cmFuZXQgQ2Vy dGlmaWNhdGUgQXV0aG9yaXR5MB4XDTAyMDYwMTIwMjIyM1oXDTAyMTEyODIwMjIyM1owfTEL MAkGA1UEBhMCVVMxGzAZBgNVBAoTEkFtZXJpY2EgT25saW5lIEluYzEXMBUGCgmSJomT8ixk AQETB2pnbXllcnMxIzAhBgkqhkiG9w0BCQEWFGpnbXllcnNAbmV0c2NhcGUuY29tMRMwEQYD VQQDEwpKb2huIE15ZXJzMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDsB5tbTLWFycke 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