Performance (iops) becomes bad, what is the reason? Post: 302531168

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Operating Systems Solaris Performance (iops) becomes bad, what is the reason? Post 302531168 by ForgetChen on Thursday 16th of June 2011 07:40:13 AM

06-16-2011

Registered User

Performance (iops) becomes bad, what is the reason?

I have written a virtual HBA driver named "xmp_vhba". A scsi disk is attached on it. as shown below:

Code:

xmp_vhba, instance #0
        disk, instance #11

But the performance became very bad when we read/write the scsi disk using the vdbench(a read/write io tool).
What is the reason? Thanks!!

the performance is shown as below:

Code:

-bash-3.00# ./vdbench -vt -f xxx.txt
Vdbench distribution: vdbench502
For documentation, see 'vdbench.pdf'.
15:23:40.130 input argument scanned: '-vt'
15:23:40.163 input argument scanned: '-fxxx.txt'
15:23:41.635 Starting slave: /export/home/vdbench502/vdbench SlaveJvm -m localhost -n localhost-10-110616-15.23.39.879 -l localhost-0 -p 5570   
15:23:43.481 All slaves are now connected
15:23:48.002 Starting RD=run1; I/O rate: Uncontrolled MAX; elapsed=900000; For loops: threads=30.0
Jun 16, 2011  interval        i/o   MB/sec   bytes   read     resp     resp     resp    cpu%  cpu%
                             rate  1024**2     i/o    pct     time      max   stddev sys+usr   sys
15:23:49.281         1   14827.00     7.24     512 100.00    1.700   22.333    0.607    20.3  15.4
15:23:50.094         2   15736.00     7.68     512 100.00    1.771   18.857    0.308    22.0  17.0
15:23:51.085         3   16376.00     8.00     512 100.00    1.790   17.089    0.238    18.9  15.5
15:23:52.083         4   16797.00     8.20     512 100.00    1.744   17.868    0.198    19.1  15.7
15:23:53.076         5   16635.00     8.12     512 100.00    1.764   18.878    0.260    19.2  15.6
15:23:54.076         6   16769.00     8.19     512 100.00    1.748   17.625    0.224    19.1  15.7
15:23:55.076         7   16752.00     8.18     512 100.00    1.750   18.424    0.266    19.0  15.6

---------- Post updated at 06:38 AM ---------- Previous update was at 03:05 AM ----------

Maybe the properties of the VHBA and the scsi disk can affect the performance. Or the vdbench cause this problem.
I don't know what are the possible reasons. Who can give me some suggestions to resolve this problem. Thanks!!

---------- Post updated at 06:40 AM ---------- Previous update was at 06:38 AM ----------

Maybe the properties of the VHBA and the scsi disk can affect the performance. Or the vdbench cause this problem.
I don't know what are the possible reasons. Who can give me some suggestions to resolve this problem. Thanks!!

ForgetChen

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tran_sync_pkt

tran_sync_pkt(9E)						Driver Entry Points						 tran_sync_pkt(9E)

NAME

       tran_sync_pkt - SCSI HBA memory synchronization entry point

SYNOPSIS

       #include <sys/scsi/scsi.h>

       void prefixtran_sync_pkt(struct scsi_address *ap, struct scsi_pkt *pkt);

INTERFACE LEVEL

       Solaris architecture specific (Solaris DDI).

PARAMETERS

       ap	A pointer to a scsi_address(9S) structure.

       pkt	A pointer to a scsi_pkt(9S) structure.

DESCRIPTION

       The  tran_sync_pkt()  vector  in  the scsi_hba_tran(9S) structure must be initialized during the HBA driver's attach(9E) to point to an HBA
       driver entry point to be called when a target driver calls scsi_sync_pkt(9F).

       tran_sync_pkt() must synchronize a HBA's or device's view of the data associated with the pkt, typically by calling  ddi_dma_sync(9F).  The
       operation  may  also  involve  HBA  hardware-specific  details,	such as  flushing I/O caches, or stalling until hardware buffers have been
       drained.

SEE ALSO

       attach(9E),   tran_init_pkt(9E),   ddi_dma_sync(9F),   scsi_hba_attach(9F),   scsi_init_pkt(9F),    scsi_sync_pkt(9F),	 scsi_address(9S),
       scsi_hba_tran(9S), scsi_pkt(9S)

       Writing Device Drivers

NOTES

       A target driver may call tran_sync_pkt() on packets for which no DMA resources were allocated.

SunOS 5.10							    1 Nov 1993							 tran_sync_pkt(9E)