Hello all, i've upgraded two machine to 2.4.21 ( from kernel.org ) and since then i've noticed this very annoying behaviour when i do a large disk write operation ( copy a big file for example ), the whole system becomes very busy ( system goes into 99% cpu utilization in kernel mode ), other tasks are stopped ( for example audio playing stops , mouse pointer moves very slowly ) etc ... I think it happens when the buffers are flushed on the disk ( i.e it migh happen a few seconds after the copy operation started ). On one machine i have Robert Love's kernel preempt patch, not on the other one. My home machine ( the one without the kernel preempt patch ) has the following config : Asus A7V8X motherboard. CPU : athlon 2400+ XP Maxtor Diamond 80GB ATA133, 10kRPM HD. 512 MB DDR 333 RAM. ext3 file system on all partitions. running hdparm -i /dev/hda gives : /dev/hda: Model=Maxtor 6Y080L0, FwRev=YAR41VW0, SerialNo=Y3H1EH8E Config={ Fixed } RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57 BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=off CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=160086528 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio1 pio2 pio3 pio4 DMA modes: mdma0 mdma1 mdma2 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 AdvancedPM=yes: disabled (255) WriteCache=enabled Drive conforms to: (null): 1 2 3 4 5 6 7 lspci gives: 00:00.0 Host bridge: VIA Technologies, Inc. VT8377 [KT400 AGP] Host Bridge 00:01.0 PCI bridge: VIA Technologies, Inc. VT8235 PCI Bridge 00:07.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host Controller (rev 46) 00:08.0 RAID bus controller: Promise Technology, Inc. PDC20376 (rev 02) 00:09.0 Ethernet controller: Broadcom Corporation BCM4401 100Base-T (rev 01) 00:0d.0 Ethernet controller: Intel Corp. 82557/8/9 [Ethernet Pro 100] (rev 08) 00:10.0 USB Controller: VIA Technologies, Inc. USB (rev 80) 00:10.1 USB Controller: VIA Technologies, Inc. USB (rev 80) 00:10.2 USB Controller: VIA Technologies, Inc. USB (rev 80) 00:10.3 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 82) 00:11.0 ISA bridge: VIA Technologies, Inc. VT8235 ISA Bridge 00:11.1 IDE interface: VIA Technologies, Inc. VT82C586/B/686A/B PIPC Bus Master IDE (rev 06) 00:11.5 Multimedia audio controller: VIA Technologies, Inc. VT8233 AC97 Audio Controller (rev 50) 01:00.0 VGA compatible controller: ATI Technologies Inc Radeon R300 NE [Radeon 9700] 01:00.1 Display controller: ATI Technologies Inc: Unknown device 4e65 lsmod gives: isofs 29172 0 (autoclean) zlib_inflate 20900 0 (autoclean) [isofs] vfat 12588 0 (autoclean) fat 37464 0 (autoclean) [vfat] sd_mod 12300 0 (autoclean) adiusbadsl 46308 2 snd-pcm-oss 44612 2 (autoclean) snd-mixer-oss 16152 1 (autoclean) [snd-pcm-oss] snd-via82xx 16576 3 (autoclean) snd-pcm 79936 0 (autoclean) [snd-pcm-oss snd-via82xx] snd-timer 19012 0 (autoclean) [snd-pcm] snd-ac97-codec 47240 0 (autoclean) [snd-via82xx] snd-page-alloc 7776 0 (autoclean) [snd-via82xx snd-pcm] snd-mpu401-uart 5028 0 (autoclean) [snd-via82xx] snd-rawmidi 17696 0 (autoclean) [snd-mpu401-uart] snd-seq-device 6004 0 (autoclean) [snd-rawmidi] snd 41252 0 (autoclean) [snd-pcm-oss snd-mixer-oss snd-via82xx snd-pcm snd-timer snd-ac97-codec snd-mpu401-uart snd-rawmidi snd-seq-device] soundcore 5924 4 (autoclean) [snd] parport_pc 31304 1 (autoclean) lp 8096 0 (autoclean) parport 33312 1 (autoclean) [parport_pc lp] ipsec 268288 1 autofs4 12212 0 (autoclean) (unused) bcm4400 30880 1 ipt_LOG 4184 1 (autoclean) ipt_limit 1560 1 (autoclean) ipt_state 1048 1 (autoclean) ipt_MASQUERADE 2200 1 (autoclean) iptable_nat 20920 1 (autoclean) [ipt_MASQUERADE] ip_conntrack 25480 2 (autoclean) [ipt_state ipt_MASQUERADE iptable_nat] iptable_filter 2412 1 (autoclean) ip_tables 14328 8 [ipt_LOG ipt_limit ipt_state ipt_MASQUERADE iptable_nat iptable_filter] sg 31340 0 (autoclean) sr_mod 17496 0 (autoclean) ide-scsi 12080 0 ohci1394 28616 0 (unused) ieee1394 59300 0 [ohci1394] printer 8896 0 usb-storage 26800 0 scsi_mod 97012 5 [sd_mod sg sr_mod ide-scsi usb-storage] mod_quickcam 41936 0 videodev 7968 1 [mod_quickcam] keybdev 2880 0 (unused) mousedev 5428 1 hid 22020 0 (unused) input 5216 0 [keybdev mousedev hid] uhci 28880 0 (unused) ehci-hcd 19784 0 (unused) usbcore 75168 1 [adiusbadsl printer usb-storage mod_quickcam hid uhci ehci-hcd] and uname -a gives: Linux xxx 2.4.21 #2 Mon Jun 16 16:10:04 CEST 2003 i686 athlon i386 GNU/Linux i'm also attaching my .config Has anyone experienced this behaviour ? this is really annoying ( it reminds me of another 'os' named winsomething .... ). -- Charles-Edouard Ruault PGP Key ID E10C24DC