Heavy disk IO stalls ftp/http downloads

hari (harisri@bigpond.com)
Fri, 23 Nov 2001 20:00:45 +0000


Hello,

When I am downloading files from the internet (using ftp command, Konqueror,
gftp etc. on 56K modem), heavy disk activity stalls the download. Stopping
the disk activity makes it to resume the download in normal speed.

For eg, when I tried downloading patch-2.4.15-final.bz2, the moment I
started copying a big (154 MB) directory (cp /usr/src/linux-2.4.14
/usr/src/linux-2.4.15-final) it stalled the download. When I terminated the
'cp' command, it resumed the download.

The output of 'vmstat 3' during the download/heavy disk activity (sampled at
5 sec):
procs memory swap io system
cpu
r b w swpd free buff cache si so bi bo in cs us sy
id
1 0 0 19576 98136 160928 150928 0 0 8 10 134 169 1 0
99
1 1 0 19576 78384 161012 170432 0 0 1672 28 1224 984 4 11
85
2 0 0 19576 60920 162880 185972 0 0 1151 761 993 803 2 10
87
2 0 0 19576 40984 164708 203952 0 0 1264 678 949 1362 5 12
83
1 1 0 19576 20580 167484 223656 0 0 1670 1089 652 1655 8 11
81
0 1 1 19576 3192 169800 238676 0 0 1668 1246 611 900 2 9
89
1 0 0 19888 3240 166100 245040 0 25 1975 794 550 798 2 8
90
0 1 2 20512 4116 156732 253568 40 17 2478 238 710 1493 10 10
79
0 1 1 20512 4360 156740 253316 0 0 6 3021 419 235 2 1
96
0 1 1 20508 4340 149260 260836 0 0 1839 0 470 743 2 6
92
1 0 0 20508 4380 147628 262416 0 0 350 2914 397 333 1 4
95
0 1 1 20508 3968 142580 267844 0 0 1590 954 437 672 2 8
90
1 1 1 20508 3908 142580 267896 0 0 5 3272 437 228 2 1
97
1 0 0 20508 3932 141744 268704 0 0 251 2717 538 904 5 4
91
0 1 0 20508 3540 131200 279608 0 0 2500 759 560 1195 5 10
85
1 0 2 21528 3384 123552 289588 0 256 1611 489 494 1088 6 8
86
2 0 0 21528 4364 119564 292792 0 0 810 2149 423 379 0 3
97
0 1 1 21528 3840 119612 293232 0 0 1102 1862 434 483 0 7
92
0 1 0 21528 3824 117780 294932 0 0 1344 605 369 494 0 7
92
0 1 0 21528 3300 120700 290288 0 0 715 1248 329 469 0 11
88
0 1 1 21528 3264 125484 285044 0 0 395 4004 412 294 0 3
97
0 0 0 21528 4364 124300 285168 0 0 487 982 333 360 1 8
91
0 0 1 21528 3344 127544 282992 0 0 0 2650 303 279 2 2
97

Hardware configuration:
AMD Athlon 1200MHz on MSI-6341 Board
512 MB RAM
2 * 10 GB IDE Hard drives (on software RAID0, enabled DMA on both drives)
External 56K Modem on serial port

Software configuration:
Linux pengu 2.4.15-pre9 #3 Thu Nov 22 19:33:35 GMT 2001 i686 unknown

Gnu C 2.95.2
Gnu make 3.79.1
binutils 2.10.0.33
util-linux 2.11b
mount 2.11b
modutils 2.4.1
e2fsprogs 1.22
PPP 2.4.0
isdn4k-utils 3.1pre1a
Linux C Library x 1 root root 1382179 Jan 19 2001
/lib/libc.so.6
Dynamic linker (ldd) 2.2
Procps 2.0.7
Net-tools 1.57
Kbd 1.02
Sh-utils 2.0
Modules Loaded iptable_filter ip_tables ppp_async ppp_generic slhc
serial emu10k1 ac97_codec soundcore ext2

Can someone please help me by letting me know where the problem could be? My
apologies if this is a known problem of some kind and there are some
workarounds.

Please cc me if you can, else I will read lkml achieves at
marc.theaimsgroup.com.

Thanks in advance.

-- 
Hari.
harisri@bigpond.com
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