Date: Sat, 21 Aug 2004 06:50:39 +1000 From: Peter Jeremy <PeterJeremy@optushome.com.au> To: freebsd-stable@freebsd.org Subject: Excessive fdisk(8) delays Message-ID: <20040820205038.GN423@cirb503493.alcatel.com.au>
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I haven't noticed this before and don't recall it being mentioned before... I just did an 'fdisk ad1' whilst ad0 was being hammered and the fdisk spat out all the expected information then hung (in "atalck") for about 4½ minutes before exiting. This was repeatable and very disconcerting the first time. Background: The system is an AMD Athlon-XP running -STABLE from the beginning of August with two 100GB WD drives running at UDMA100 attached to channel 0 of a VIA VT8233A. The "hammering" was a dd of the raw disk, a "find /" and a "cvs update" (systat -v report 100% utilisation of ad0). A quick check of the code shows "atalck" is used within ATA_SLEEPLOCK_CH to wait for the channel to be come idle and this macro is used fairly extensively within the ata code. Having I/O requests queued for over 4 minutes seems excessive - how difficult would it be for the ata code to better round-robin requests? (Possibly via a wakeup at the end of ata_start()). -- Peter Jeremy
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