SuSE Linux: Versionen bis einschließlich 7.0
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CONFIG_AIC7XXX_TCQ_ON_BY_DEFAULT This option causes the aic7xxx driver to attempt to use tagged command queueing on any devices that claim to support it. If this is set to yes, you can still turn off TCQ on troublesome devices with the use of the tag_info boot parameter. See /usr/src/linux/drivers/scsi/README.aic7xxx for more information on that and other aic7xxx setup commands. If this option is turned off, you may still enable TCQ on known good devices by use of the tag_info boot parameter. If you are unsure about your devices then it is safest to say N here. However, TCQ can increase performance on some hard drives by as much as 50% or more, so I would recommend that if you say N here, that you at least read the README.aic7xxx file so you will know how to enable this option manually should your drives prove to be safe in regards to TCQ. Conversely, certain drives are known to lock up or cause bus resets when TCQ is enabled on them. If you have a Western Digital Enterprise SCSI drive for instance, then don't even bother to enable TCQ on it as the drive will become unreliable, and it will actually reduce performance.Es scheint nun so zu sein, dass dieses nicht eingeschaltete Feature einen starken Einfluss auf die Plattenperformance einiger IBM SCSI Festplatten hat -- ohne dass wir dieses Verhalten auf anderen Systemen bisher bemerkt hatten.
zgrep TCQ /proc/config.gzWenn Sie mit einem älteren Kernel arbeiten, überprüfen Sie bitte die Kernelkonfigurationsdatei.
# CONFIG_AIC7XXX_TCQ_ON_BY_DEFAULT is not setAuf Systemen mit SuSE Linux 7.1 und anderen Systemen, bei denen TCQ eingeschaltet ist, werden Sie folgende Nachricht erhalten:
CONFIG_AIC7XXX_TCQ_ON_BY_DEFAULT=yGlücklicherweise müssen Sie den Kernel nicht neu kompilieren, um TCQ zu verwenden. Sie können dem Kernel über einen Bootparameter mitteilen, dass TCQ für bestimmte Laufwerke eingeschaltet werden soll.
"aic7xxx=tag_info:{{8,8..},{8,8..},..}" This option is used to disable or enable Tagged Command Queueing (TCQ) on specific devices. As of driver version 5.1.11, TCQ is now either on or off by default according to the setting you choose during the make config process. In order to en/disable TCQ for certian devices at boot time, a user may use this boot param. The driver will then parse this message out and en/disable the specific device entries that are present based upon the value given. The param line is parsed in the following manner: { - first instance indicates the start of this parameter values second instance is the start of entries for a particular device entry } - end the entries for a particular host adapter, or end the entire set of parameter entries , - move to next entry. Inside of a set of device entries, this moves us to the next device on the list. Outside of device entries, this moves us to the next host adapter . - Same effect as , but is safe to use with insmod. x - the number to enter into the array at this position. 0 = Enable tagged queueing on this device and use the default queue depth 1-254 = Enable tagged queueing on this device and use this number as the queue depth 255 = Disable tagged queueing on this device. Note: anything above 32 for an actual queue depth is wasteful and not recommended. A few examples of how this can be used: tag_info:{{8,12,,0,,255,4}} This line will only effect the first aic7xxx card registered. It will set scsi id 0 to a queue depth of 8, id 1 to 12, leave id 2 at the default, set id 3 to tagged queueing enabled and use the default queue depth, id 4 default, id 5 disabled, and id 6 to 4. Any not specified entries stay at the default value, repeated commas with no value specified will simply increment to the next id without changing anything for the missing values. tag_info:{,,,{,,,255}} First, second, and third adapters at default values. Fourth adapter, id 3 is disabled. Notice that leading commas simply increment what the first number effects, and there are no need for trailing commas. When you close out an adapter, or the entire entry, anything not explicitly set stays at the default value. A final note on this option. The scanner I used for this isn't perfect or highly robust. If you mess the line up, the worst that should happen is that the line will get ignored. If you don't close out the entire entry with the final bracket, then any other aic7xxx options after this will get ignored. So, in general, be sure of what you are entering, and after you have it right, just add it to the lilo.conf file so there won't be any mistakes. As a means of checking this parser, the entire tag_info array for each card is now printed out in the /proc/scsi/aic7xxx/x file. You can use that to verify that your options were parsed correctly.Ein Einschalten des Tagged Command Queueings mit Hilfe der Bootparameter steigert die Performance der betroffenen Systeme dramatisch.
liloHinweis: Unser Kunde Herr Griem teilte uns mit, dass es bei der Benutzung der options-Zeile in der Datei /etc/modules.conf und gleichzweitiger Verwendung der initial ramdisk zu Problemen kommen kann, wenn als Trennzeichen das Komma (,) verwendet wird. In /usr/src/linux/drivers/scsi/README.aic7xxx wird dazu erwähnt:
Module Loading command options ------------------------------ When loading the aic7xxx driver as a module, the exact same options are available to the user. However, the syntax to specify the options changes slightly. For insmod, you need to wrap the aic7xxx= argument in quotes and replace all ',' with '.'. So, for example, a valid insmod line would be: insmod aic7xxx aic7xxx='verbose.irq_trigger:1.extended'Ersetzen Sie also alle Kommata durch Punkte.