From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 20 Aug 2001 17:11:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 20 Aug 2001 17:11:10 -0400 Received: from [213.4.18.231] ([213.4.18.231]:23826 "EHLO fulanito.nisupu.com") by vger.kernel.org with ESMTP id ; Mon, 20 Aug 2001 17:10:57 -0400 Message-ID: <009501c129bc$75724ca0$0414a8c0@10> From: =?iso-8859-1?Q?Carlos_Fern=E1ndez_Sanz?= To: "Ignacio Vazquez-Abrams" , =?iso-8859-1?Q?Carlos_Fern=E1ndez_Sanz?= Cc: In-Reply-To: Subject: Re: Fw: select(), EOF... Date: Mon, 20 Aug 2001 23:09:53 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org a strace shows it works differently nanosleep({1, 0}, {1, 0}) = 0 fstat(3, {st_mode=S_IFREG|0600, st_size=227128, ...}) = 0 rt_sigprocmask(SIG_BLOCK, [CHLD], [RT_0], 8) = 0 rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0 rt_sigprocmask(SIG_SETMASK, [RT_0], NULL, 8) = 0 the file is opened just once (as I expected), and tail sleeps in nanosleep () until the file grows. I think strace isn't showing more nanosleep() as it should be looping there. BTW what's the reason for the sigprocmask, etc? ----- Original Message ----- From: "Ignacio Vazquez-Abrams" To: "Carlos Fernández Sanz" Cc: Sent: Monday, August 20, 2001 11:00 PM Subject: Re: Fw: select(), EOF... > On Mon, 20 Aug 2001, Carlos Fernández Sanz wrote: > > > How come the process is never runnable unless there's new data in the file? > > If it was opening and closing the file continously it would be using lots of > > CPU, while it's 0 if there's no data coming. > > It sleep()s between close() and open(). > > -- > Ignacio Vazquez-Abrams > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >