I have two servers connected via Gigabit Ethernet. One is iSCSI target, the second one is initiator. When I run mkfs.ext4 at initiator, after a while disk IO slows down critically. In the target host I can see the following in syslog:

Sep 14 09:40:03 sh11 tgtd: abort_task_set(1139) found 119668c 0
Sep 14 09:40:03 sh11 tgtd: abort_cmd(1115) found 119668c 6
Sep 14 09:40:03 sh11 tgtd: abort_task_set(1139) found 119668d 0
Sep 14 09:40:03 sh11 tgtd: abort_cmd(1115) found 119668d 6
Sep 14 09:40:03 sh11 tgtd: abort_task_set(1139) found 119668e 0
Sep 14 09:40:03 sh11 tgtd: abort_cmd(1115) found 119668e 6
Sep 14 09:40:03 sh11 tgtd: abort_task_set(1139) found 1196696 0
Sep 14 09:40:03 sh11 tgtd: abort_cmd(1115) found 1196696 6
Sep 14 09:40:03 sh11 tgtd: abort_task_set(1139) found 119669e 0
Sep 14 09:40:03 sh11 tgtd: abort_cmd(1115) found 119669e 6
Sep 14 09:40:04 sh11 tgtd: abort_task_set(1139) found 119669f 0
Sep 14 09:40:04 sh11 tgtd: abort_cmd(1115) found 119669f 6

And load average grows to 12 or even more:

# uptime
 12:37:00 up 23 days, 13:25,  1 user,  load average: 12.00, 7.00, 4.00

• CentOS 6.3
• tgtd 1.0.24
• Intel Pentium 4 2.4GHz
• 1Gb RAM
• 2Tb WD Cavlar Green SATA 2.0

#lspci
00:00.0 Host bridge: Intel Corporation 82845G/GL[Brookdale-G]/GE/PE DRAM Controller/Host-Hub Interface (rev 02)
00:01.0 PCI bridge: Intel Corporation 82845G/GL[Brookdale-G]/GE/PE Host-to-AGP Bridge (rev 02)
00:1d.0 USB controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 02)
00:1d.1 USB controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 02)
00:1d.2 USB controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 02)
00:1d.7 USB controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 82)
00:1f.0 ISA bridge: Intel Corporation 82801DB/DBL (ICH4/ICH4-L) LPC Interface Bridge (rev 02)
00:1f.1 IDE interface: Intel Corporation 82801DB (ICH4) IDE Controller (rev 02)
00:1f.3 SMBus: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) SMBus Controller (rev 02)
00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 02)
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RV200 QW [Radeon 7500]
02:01.0 Ethernet controller: D-Link System Inc DGE-530T Gigabit Ethernet Adapter (rev 11) (rev 11)
02:02.0 RAID bus controller: VIA Technologies, Inc. VT6421 IDE/SATA Controller (rev 50)
02:03.0 RAID bus controller: VIA Technologies, Inc. VT6421 IDE/SATA Controller (rev 50)
02:04.0 RAID bus controller: Silicon Image, Inc. SiI 3114 [SATALink/SATARaid] Serial ATA Controller (rev 02)
02:08.0 Ethernet controller: Intel Corporation 82801DB PRO/100 VE (CNR) Ethernet Controller (rev 82)

Is there a way to tune target host to avoid these timeouts?