Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 12 Nov 2000 18:54:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 12 Nov 2000 18:54:47 -0500 Received: from 47-ZARA-X8.libre.retevision.es ([62.82.228.175]:12551 "EHLO head.redvip.net") by vger.kernel.org with ESMTP id ; Sun, 12 Nov 2000 18:54:33 -0500 Message-ID: <3A0F28AB.1E2A28E8@zaralinux.com> Date: Mon, 13 Nov 2000 00:32:59 +0100 From: Jorge Nerin X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.0-test10 i586) X-Accept-Language: es-ES, es, en MIME-Version: 1.0 To: bb@ricochet.net, Linux Kernel Mailing List Subject: Documentation/proc.txt update Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello, this is a patch with some updates to the Documetation/proc.txt file, basically it contains updates to the new files in /proc/, new files in /proc, and a paragraph about /proc/sys/net/ipv4/tcp_ecn. It's far from complete, but it's a start point. --- old/proc.txt Mon Oct 23 15:20:00 2000 +++ new/proc.txt Mon Nov 13 00:20:24 2000 @@ -46,7 +46,7 @@ the SuSE Linux distribution. As there is no complete documentation for the /proc file system and we've used many freely available sources to write these chapters, it seems only fair to give the work back to the Linux community. -This work is based on the 2.2.* kernel version. I'm afraid it's still far from +This work is based on the 2.2.* kernel version and the upcomming 2.4.*. I'm afraid it's still far from complete, but we hope it will be useful. As far as we know, it is the first 'all-in-one' document about the /proc file system. It is focused on the Intel x86 hardware, so if you are looking for PPC, ARM, SPARC, APX, etc., features, @@ -92,7 +92,7 @@ The proc file system acts as an interface to internal data structures in the kernel. It can be used to obtain information about the system and to change -certain kernel parameters at runtime. +certain kernel parameters at runtime (sysctl). First, we'll take a look at the read-only parts of /proc. In Chapter 2, we show you how you can use /proc/sys to change settings. @@ -111,16 +111,17 @@ .............................................................................. File Content cmdline Command line arguments - environ Values of environment variables + cpu Current and last cpu in wich it was executed (2.4)(smp) + cwd Link to the Current Working Directory + environ Values of environment variables + exe Link to the executable in the filesystem fd Directory, which contains all file descriptors + maps Maps to executables and library files (2.4) mem Memory held by this process + root Link to the root directory of this process stat Process status - status Process status in human readable form - cwd Link to the current working directory - exe Link to the executable of this process - maps Memory maps - root Link to the root directory of this process statm Process memory status information + status Process status in human readable form .............................................................................. For example, to get the status information of a process, all you have to do is @@ -131,6 +132,7 @@ State: R (running) Pid: 5452 PPid: 743 + TracerPid: 0 (2.4) Uid: 501 501 501 501 Gid: 100 100 100 100 Groups: 100 14 16 @@ -187,13 +189,20 @@ devices Available devices (block and character) dma Used DMS channels filesystems Supported filesystems + driver Various drivers grouped here, currently rtc (2.4) + execdomains Execdomains, related to security (2.4) + fb Frame Buffer devices (2.4) + fs File system parameters, currently nfs/exports (2.4) ide Directory containing info about the IDE subsystem interrupts Interrupt usage + iomem Memory map (2.4) ioports I/O port usage - kcore Kernel core image (can be ELF or A.OUT) + irq Masks for irq to cpu affinity (2.4)(smp?) + isapnp ISA PnP (Plug&Play) Info (2.4) + kcore Kernel core image (can be ELF or A.OUT(depreciated in 2.4)) kmsg Kernel messages ksyms Kernel symbol table - loadavg Load average + loadavg Load average of last 1, 5 & 15 minutes locks Kernel locks meminfo Memory info misc Miscellaneous @@ -201,14 +210,19 @@ mounts Mounted filesystems net Networking info (see text) partitions Table of partitions known to the system + pci Depreciated info of PCI bus (new way -> /proc/bus/pci/, + decoupled by lspci (2.4) rtc Real time clock scsi SCSI info (see text) slabinfo Slab pool info stat Overall statistics swaps Swap space utilization sys See chapter 2 + sysvipc Info of SysVIPC Resources (msg, sem, shm) (2.4) + tty Info of tty drivers uptime System uptime version Kernel version + video bttv info of video resources (2.4) .............................................................................. You can, for example, check which interrupts are currently in use and what @@ -230,6 +244,68 @@ 15: 7 XT-PIC ide1 NMI: 0 +In 2.4.* a couple of lines where added to this file LOC & ERR (this time is the +output of a SMP machine): + + > cat /proc/interrupts + + CPU0 CPU1 + 0: 1243498 1214548 IO-APIC-edge timer + 1: 8949 8958 IO-APIC-edge keyboard + 2: 0 0 XT-PIC cascade + 5: 11286 10161 IO-APIC-edge soundblaster + 8: 1 0 IO-APIC-edge rtc + 9: 27422 27407 IO-APIC-edge 3c503 + 12: 113645 113873 IO-APIC-edge PS/2 Mouse + 13: 0 0 XT-PIC fpu + 14: 22491 24012 IO-APIC-edge ide0 + 15: 2183 2415 IO-APIC-edge ide1 + 17: 30564 30414 IO-APIC-level eth0 + 18: 177 164 IO-APIC-level bttv + NMI: 2457961 2457959 + LOC: 2457882 2457881 + ERR: 2155 + +NMI is incremented in this case because every timer interrupt generates a NMI +(Non Maskable Interrupt) which is used by the NMI Watchdog to detect lookups. + +LOC is the local interrupt counter of the internal APIC of every CPU. + +ERR is incremented in the case of errors in the IO-APIC bus (the bus that +connects the CPUs in a SMP system. This means that an error has been detected, +the IO-APIC automatically retry the transmision, so it should not be a big +problem, but you should read the SMP-FAQ. + +In this context it could be interesting to note the new irq directory in 2.4. +It could be used to set IRQ to CPU affinity, this means that you can "hook" an +IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the +irq subdir is one subdir for each IRQ, and one file; prof_cpu_mask + +For example + > ls /proc/irq/ + 0 10 12 14 16 18 2 4 6 8 prof_cpu_mask + 1 11 13 15 17 19 3 5 7 9 + > ls /proc/irq/0/ + smp_affinity + +The contents of the prof_cpu_mask file and each smp_affinity file for each IRQ +is the same by default: + + > cat /proc/irq/0/smp_affinity + ffffffff + +It's a bitmask, in wich you can specify wich CPUs can handle the IRQ, you can +set it by doing: + + > echo 1 > /proc/irq/prof_cpu_mask + +This means that only the first CPU will handle the IRQ, but you can also echo 5 +wich means that only the first and fourth CPU can handle the IRQ. + +The way IRQs are routed is handled by the IO-APIC, and it's Round Robin +between all the CPUs which are allowed to handle it. As usual the kernel has +more info than you and does a better job than you, so the defaults are the +best choice for almost everyone. There are three more important subdirectories in /proc: net, scsi, and sys. The general rule is that the contents, or even the existence of these @@ -1306,6 +1382,15 @@ TCP settings ------------ + +tcp_ecn +------- + +This file controls the use of the ECN bit in the IPv4 headers, this is a new +feature about Explicit Congestion Notification, but some routers and firewalls +block trafic that has this bit set, so it could be necessary to echo 0 to +/proc/sys/net/ipv4/tcp_ecn, if you want to talk to this sites. For more info +you could read RFC2481. tcp_retrans_collapse -------------------- -- Jorge Nerin - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/