Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263335AbTECPNR (ORCPT ); Sat, 3 May 2003 11:13:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263336AbTECPNR (ORCPT ); Sat, 3 May 2003 11:13:17 -0400 Received: from siaag1ab.compuserve.com ([149.174.40.4]:22744 "EHLO siaag1ab.compuserve.com") by vger.kernel.org with ESMTP id S263335AbTECPNQ (ORCPT ); Sat, 3 May 2003 11:13:16 -0400 Date: Sat, 3 May 2003 11:24:09 -0400 From: Chuck Ebbert <76306.1226@compuserve.com> Subject: Re:[PATCH][Experimental] Debugging i386 using hardware task switching To: linux-kernel Message-ID: <200305031125_MC3-1-3736-8D55@compuserve.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2049 Lines: 48 Buoyed by the success of silly usermode testing, I got brave and stuck an int3 instruction right in the middle of arch/i386/kernel/irq.c:do_IRQ() and captured this: *1 - EIP is at do_IRQ+0x38, with interrupts disabled *2 - 0x50 (80) bytes of kernel stack are in use *3 - ECX: last two interrupts were 199485 clocks apart (boot CPU speed is 199.491 MHz) *4 - ESI: int3 has been invoked 1653673 times since boot This is with an SMP kernel on a 1-CPU machine. The 1000 clocks of extra overhead every interrupt don't seem to make much of a difference... GDT entry #16: kernel TSS at c0393800, 236 bytes: CS:0060 EIP:c010afa8 eflags:00000002 *1 SS0:0068 ESP0:c2966000 SS1:0060 ESP1:c0393a00 SS2:0000 ESP2:00000000 SS:0068 ESP:c2965fb0 *2 DS:007b ES:007b FS:0000 GS:0000 EAX:c10a2020 EBX:00000000 ECX:00cb5f80 EDX:00000000 ESI:c0393c00 EDI:00000000 EBP:bffffb78 BITMAP:8000 LDT:0088 CR3:035d1000 LINK:0000 GDT entry #30: debugger TSS at c0395a00, 236 bytes: CS:0060 EIP:c0110173 eflags:00000006 SS0:0068 ESP0:c03f27a0 SS1:0000 ESP1:00000000 SS2:0000 ESP2:00000000 SS:0068 ESP:c03f27a0 DS:007b ES:007b FS:0000 GS:0000 EAX:aa72bbf2 EBX:c0341a40 ECX:00030b3d EDX:0000004e *3 ESI:00193ba9 EDI:00000010 EBP:c03f03a0 BITMAP:8000 LDT:0088 CR3:00101000 LINK:0080 *4 - 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/