SGI Performance Comparisons

Copying Many Smaller Files Straight to Disk

Last Change: 08/May/2008

This test uses the IRIS Development Option 7.1 CD for IRIX 6.3, which has an 'insight' directory containing approximately 2200 files, representing some 76289K (74.5MB) of data, giving an average file size of 35K. I timed how long the various systems took to copy the insight directory straight to disk. The destination was always /var/tmp/t (an empty directory), and all tests were performed using IRIX 6.5. Data rates are in KBytes/sec. The command sequence used to run the test, which was entered into a raw xterm where the current working directory was /CDROM, was:

   timex tar cBpf - insight | ( cd /var/tmp/t ; tar xBpf - )


Results for Origin200 R10000SC 180MHz (1MB L2):

CDROM     Time     Data
Speed    (m:ss)    Rate

  2X      
 32X      1:18      978

        Table 41


Results for O2 R5000SC 200MHz (the 12X is the O2's internal CDROM):

CDROM     Time     Data
Speed    (m:ss)    Rate

  2X      4:46     267
 12X      2:24     530
 32X      1:48     706

        Table 27


Results for Indigo2 250MHz R4400SC:

CDROM     Time     Data
Speed    (m:ss)    Rate

  2X      4:50     263
 32X      1:48     706

        Table 28


Results for Indy 200MHz R4400SC:

CDROM     Time     Data
Speed    (m:ss)    Rate

  2X      5:02     253
 32X      2:03     620

        Table 29


Results for Indy 133MHz R4600PC:

CDROM     Time     Data
Speed    (m:ss)    Rate

  2X      5:22     237
 32X      3:24     374

        Table 30


Results for Indy 100MHz R4600PC:

CDROM     Time     Data
Speed    (m:ss)    Rate

  2X      5:27     233
 32X      3:26     370

        Table 31


Compared to copying a single large file, the average transfer rate is clearly much reduced. So much so in fact that, when transferring many small files, a system can easily display an average transfer rate for a 32X CDROM which is lower than that given by a 2X CDROM for transferring a single large file. Thus, don't assume a fast CDROM is going to display a level of performance that's anywhere near its theoretical maximum - it all depends on the task in question.

Also, faster systems do proportionally better than slower systems when transferring lots of small files, ie. the better main CPU helps a lot in dealing with the file-creation overhead. Here are the summary tables:

                         Time     Data
                        (m:ss)    Rate

O2 R5000SC 200MHz 1MB:   4:46     267
Indigo2 250MHz R4400SC:  4:50     263
Indy 200MHz R4400SC:     5:02     253
Indy 133MHz R4600PC:     5:22     237
Indy 100MHz R4600PC:     5:27     233

   Table 32: 2X CDROM Performance
   Copying many small files to disk.


                         Time     Data
                        (m:ss)    Rate

O2 R5000SC 200MHz 1MB:   1:48     706
Indigo2 250MHz R4400SC:  1:48     706
Indy 200MHz R4400SC:     2:03     620
Indy 133MHz R4600PC:     3:24     374
Indy 100MHz R4600PC:     3:26     370

   Table 33: 32X CDROM Performance
   Copying many small files to disk.


Compare Table 33 to Table 22, and Table 32 to Table 21.