Solaris 10 Thread/LWP Schduling and I/O

Question

Hi,
I am using Solaris 10 on N440, 4CPU machine and java 1.5.
In my code there is a server socket listener thread.
On new connection a worker thread is assigned to it.
This worker thread simply reads data from the connection socket and
put on a queue. Another Thread known as FileWriterThread which
encapsulates this
queue, reads from this queue and writes to its own file. For each
connection
there is a dedicated file.
~ (Connection 1 Thread) ---> puts on Queue in ~
(FileWriterThread_1) ---> Writes to Own File 1
~ (Connection 2 Thread) ---> puts on Queue in ~
(FileWriterThread_2 ) ---> Writes to Own File 2
~ (Connection 3 Thread) ---> puts on Queue in ~
(FileWriterThread_3 ) ---> Writes to Own File 3
~ (Connection 2 Thread) ---> puts on Queue in ~
(FileWriterThread_4 ) ---> Writes to Own File 4
There could be at max 8 such connections.....
Now the debate is that to have only one FileWriterThread for all
connection Threads or Queues. Because the Write on Solaris file system
is not interleaved and even if all 4 FileWriterThread_(1,2,3,4) get
schd on each CPU since Write in Solaris file system writes one Block
at a time is not interleaved, three threads out of 4 will be preempted
and will have context switch.
Where as if there is only one FileWriterThread then on circular basis
it can fetch data from Queue and will never go for context swtich
until its TimeSlice is over. Having one thread will give better
performance than having 4 threads to write to their own file.
TIA,
Indresh MAlik

Answer 1

Try 'iostat -En' to see if find anything unsual about the disks. It probably seems to be a disk failure.
-Rai