Why did httpd load spike on Red Hat Enterprise Linux 5.6?

Issue

• Why did httpd load spike on Red Hat Enterprise Linux 5.6?
• Top out put :

top - 14:05:39 up 103 days,  4:26,  3 users,  load average: 3.05, 3.10, 3.08
Tasks: 122 total,   5 running, 117 sleeping,   0 stopped,   0 zombie
Cpu0  : 63.6%us,  0.1%sy,  0.0%ni, 36.3%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu1  : 63.9%us,  0.1%sy,  0.0%ni, 36.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   2058712k total,  2030248k used,    28464k free,   689712k buffers
Swap:  4096564k total,        8k used,  4096556k free,  1047908k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
32618 apache    25   0  131m 5008 2100 R 99.0  0.2   2140:48 httpd
32628 apache    25   0  131m 4980 2100 R 52.8  0.2   1967:29 httpd
32612 apache    25   0  131m 4648 1772 R 47.1  0.2   2180:29 httpd

• Strace of htppd pid 13028

strac]#strace -p 13028
Process 13028 attached - interrupt to quit
select(0, NULL, NULL, NULL, {0, 683000}) = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
wait4(-1, 0x7fffb1eb0cbc, WNOHANG|WSTOPPED, NULL) = 0
select(0, NULL, NULL, NULL, {1, 0} <unfinished ...>
Process 13028 detached