Abstract:
A method for determining appropriate adjustments of computer system parameter values in order to improve system performance. The method for this determination is based on historical performance data. Methods are disclosed which involve measuring current system performance and retrieving paired stored values of measured system performance and a selected system parameter. The decision as to whether or not to adjust the value of the selected system parameter is based on performing a trend analysis on the paired values. When such changes are made, subsequent measurement of system performance is performed and beneficial changes are implemented.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to computer systems and, more particularly, to the automatic adjustment of parameters to values that result in optimal system performance even as the workload on the system continues to change. 
     BACKGROUND OF THE INVENTION 
     Administrators of modern computing systems generally have various parameters available that can be adjusted or configured to values that result in improved performance of the system. Size of swap space, memory dedicated to buffer-cache, maximum number of processes permitted, and maximum application data size are examples of such parameters that could be so adjusted. 
     With limited success, various techniques have been used to make these parameter adjustments. One common solution to this problem is for the administrator or operator to learn the details of the inner workings or operation of each application, and then speculate as to the optimal configuration of the computer system. This approach has several disadvantages: (1) it is extremely time consuming, especially since it must be repeated as each new application or workload is brought into the system, (2) there is frequently insufficient data available from the vendor of the applications to do this with any precision, (3) it is an error prone process as there are often unforseen dependencies that make such speculation highly inaccurate, and (4) optimal system parameter values can be dependent upon application usage characteristics, which can vary from time to time. 
     Another solution to this problem is to build a separate mechanism for each system parameter that influences system performance and that can be adjusted. Each such mechanism would have the capability of measuring system metrics and evaluating whether or not a change in the parameter controlled by that mechanism is called for. For example, such a mechanism could control a system&#39;s virtual memory and could detect when the system either has or is in danger of running out of virtual memory. The mechanism could then recommend that the system be reconfigured to increase virtual memory. One problem with this approach is that a separate mechanism must be created for each system parameter that it is desirable to control. 
     Thus, there is a need for a method by which a computer system can be more effectively and efficiently improved. In particular, there is a need for a method to automatically and continually adjust system parameters to obtain improved system performance, even as the workload on the system changes. 
     SUMMARY OF THE INVENTION 
     The present patent document relates to a novel method for improving computer system performance by the adjustment of computer system parameters. This method can make appropriate adjustments even as the workload on the system changes. The method takes advantage of historical data regarding computer system performance and values of computer system parameters. Methods of selecting a new parameter value based upon this data are described including, but not limited to least squares line and curve fitting. 
     The methods describe comprise (1) selecting a computer system parameter for analysis and potential adjustment, (2) measuring the current value of computer system performance, (3) identifying the current value of a selected computer system parameter, (4) retrieving paired stored values of measured computer system performance and associated selected computer system parameter, (5) performing a trend analysis is performed on the paired values of computer system performance and selected computer system parameter, (6) storing the current paired current values of the measured computer system performance and the selected computer system parameter, (7) deciding whether or not to change the selected computer system parameter, and (8) if the decision is to change the value of the selected computer system parameter, making that change. This process can be repeated for other computer system parameters. In representative embodiments, tables for maintaining and displaying computer system parameter values and measured computer system performance are described. 
     While embodiments disclosed in the present patent document refer to automatic adjustment of computer system parameters, it should be recognized that such adjustments could be made by other means, as for example manually. 
     Representative embodiments as described in the present patent document are advantageous in that they take very little time or effort on the part of the system operator to arrive at an optimal or near optimal system configuration. Additionally, as the usage characteristics and load on the system change, this method finds and recommends improvements to the system, without requiring the operator to continuously monitor and redo previous adjustments that were performed by hand. Another benefit is that this mechanism can be used on a subset of the parameters available on a system. Thus, the operator may choose to use this method to look for improvements in obscure or less understood parameters, and make the macroscopic adjustments himself. 
     In addition, this method can be used “offline”. This method can be employed on a development or benchmark instance of the application, instead of on the production version. Improved settings could be found with very consumption of operator time, and without risking adverse affects on a production system. The ideal settings obtained using the development system could then be adapted to the production system. 
     Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings provide visual representations which will be used to more fully describe the invention and can be used by those skilled in the art to better understand it and its inherent advantages. In these drawings, like reference numerals identify corresponding elements and: 
     FIG. 1A is an example graph of computer system performance vs. computer system parameter value as described in various representative embodiments of the present patent document. 
     FIG. 1B is another example graph of computer system performance vs. computer system parameter value as described in various representative embodiments of the present patent document. 
     FIG. 2 is a drawing of a flow chart for a method for adjustment of computer system parameters as described in various representative embodiments of the present patent document. 
     FIG. 3 is a table of system performance for various combinations of values for a first computer parameter and a second computer system parameter as described in various representative embodiments of the present patent document. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in the drawings for purposes of illustration, the present patent document relates to a novel method for improving computer system performance by the adjustment of computer system parameters. This method can make appropriate adjustments even as the workload on the system changes. Previous methods for improving system performance have relied upon speculation as to the optimal system configuration or by independently controlling individual system parameters. In the following detailed description and in the several figures of the drawings, like elements are identified with like reference numerals. 
     FIG. 1A is an example graph  100  of computer system performance  105  vs. computer system parameter value  110  as described in various representative embodiments of the present patent document. The graph of FIG. 1A is an example of the type of data and techniques that could be used in adjusting computer system parameter values  110  in order to obtain improved computer system performance  105 . The graph of FIG. 1A is for illustrative purposes only and should not be construed as limiting the claims of the present patent document. Previously measured values of computer system performance  105  for various computer system parameter values  110  are indicated by a first, second, and third data points  115 , 116 , 117  which in FIG. 1A are indicated by X&#39;s. Current measured value of computer system performance  105  for current computer system parameter value  110  is indicated by a current data point  120  which in FIG. 1A is indicated by a circle. A best fit line  125  is drawn using the four data points  115 , 116 , 117 , 120 . The best fit line  125  could be obtained via trend analysis methods, including, but not limited to a visual best fit to the data and a sum of least squares. In the sum of least squares method, the best fit line  125  is obtained by minimizing the sum of the squares of the deviations of the data points  115 , 116 , 117 , 120  from the line  125 . 
     In order to improve the performance of a computer system whose performance is plotted in FIG. 1A to a projected level  130 , the best fit line  125  is extended to include this value. The projected computer system performance  130  intersects the best fit line  125  at projected data point  135  having projected computer system parameter value  140 . The computer system parameter value  110  is then adjusted to the projected computer system parameter value  140 , and the computer system operated at that value. Measurements of computer system performance  105  could then be made to confirm the projection just made. Additional improvements could then be made by repeating the above procedures. However, should the computer system performance  105  obtained be less than that previously obtained, appropriate adjustment to the computer system parameter value  110  could then be made to return the system to a greater performance level. 
     FIG. 1B is another example graph  150  of computer system performance  105  vs. computer system parameter value  110  as described in various representative embodiments of the present patent document. The graph of FIG. 1B is another example of the type of data and techniques that could be used in adjusting computer system parameter values  110  in order to obtain improved computer system performance  105 . The graph of FIG. 1B is for illustrative purposes only and should not be construed as limiting the claims of the present patent document. Previously measured values of computer system performance  105  for various computer system parameter values  110  are indicated by a first, second, and third data points  165 , 166 , 167  which in FIG. 1B are indicated by X&#39;s. Current measured value of computer system performance  105  for current computer system parameter value  110  is indicated by a current data point  170  which in FIG. 1B is indicated by a circle. A best fit curve  175  is drawn using the four data points  165 , 166 , 167 , 170 . The best fit curve  175  could be obtained via different trend analysis methods, including, but not limited to a visual best fit to the data and a sum of least squares for a polynomial curve. The polynomial could comprise linear, square, and higher order terms. In the sum of least squares method, the best fit curve  175  is obtained by minimizing the sum of the squares of the deviations of the data points  165 , 166 , 167 , 170  from the curve  175 . 
     In order to improve the performance of a computer system whose performance is plotted in FIG. 1B to the projected level  130 , the best fit curve  175  is extended if need be to include this value. The projected computer system performance  130  intersects the best fit curve  175  at projected data point  185  having projected computer system parameter value  140 . The computer system parameter value  110  is then adjusted to the projected computer system parameter value  140 , and the computer system operated at that value. Measurements of computer system performance  105  could then be made to confirm the projection just made. Additional improvements could then be made by repeating the above procedures. However, should the computer system performance  105  obtained be less than that previously obtained, appropriate adjustment to the computer system parameter value  110  could then be made to return the system to a greater performance level. 
     FIG. 2 is a drawing of a flow chart  200  for a method for adjustment of computer system parameters  110  as described in various representative embodiments of the present patent document. In block  212  of FIG. 2, a computer system parameter  110  is selected for analysis and potential adjustment. Block  212  then transfers control to block  215 . 
     In block  215 , a current value of computer system performance  105  is measured. Block  215  then transfers control to block  220 . 
     In block  220  the current value of the selected computer system parameter  110  is identified. This identification could be obtained, for example, via a measurement of the parameter  110 , a dial setting, a stored value, or by other means. Block  220  then transfers control to block  225 . 
     In block  225  paired stored values of measured computer system performance  105  and the selected computer system parameter  110  are retrieved. These paired values could be obtained, for example, by reading their values from a file, a database, from active computer memory, or by other means. The paired values retrieved could be limited by various criteria including, but not limited to, the age of the data selected. Block  225  then transfers control to block  230 . 
     In block  230  a trend analysis is performed on the paired values of computer system performance  105  and selected computer system parameter  110 . This trend analysis could be performed as previously discussed in reference to FIGS. 1A and 1B. Block  230  then transfers control to block  235 . 
     In block  235  the paired current values of the measured computer system performance  105  and the selected computer system parameter  110  are stored. These values could be, for example, stored in a file, a data base, in active computer system memory, or other means. Block  235  then transfers control to block  240 . 
     In block  240  a decision is made as to whether or not to change the selected computer system parameter  110 . This decision could be made based upon various criteria including, but not limited to, the deviation from the optimum or improved computer system performance  105  from the current value as indicated by the best fit line or curve. If the value of the selected system parameter  110  is to be changed, block  240  then transfers control to block  250 . Otherwise, block  240  transfers control to block  212 . 
     In block  250  the value of the selected computer system parameter  110  is changed. Block  250  then transfers control to block  212 . 
     FIG. 3 is a table  300  of computer system performance  105  for various combinations of values for a first computer system parameter  311  and a second computer system parameter  312  as described in various representative embodiments of the present patent document. The data of FIG. 3 is representative of a computer system having two significant parameters  311 , 312  or in which other computer system parameters  110  are constant or whose variability has little effect upon the computer system performance  105  obtained. In the first row under the “First Parameter”  311  heading are listed various values—P 1 (1), P 1 (2), P 1 (3), . . . —for the first computer system parameter  311 . In the first column to the right of the column containing the heading “Second Parameter”  312  are listed various values—P 2 (1), P 2 (2), P 2 (3), . . . —for the second computer system parameter  312 . While at the intersection of the column representing the ith value for the first parameter P 1 (I) and the row representing the jth value for the second parameter P 2 (j), the computer system performance  105  obtained for the combination of those two system parameters is the S(i,j). 
     However, in practical computer systems the problem is generally more complex with several significant computer system parameters  110  affecting computer system performance  105  as expressed in the following equation: 
     
       
           S ( P   1 ( I ), P   2 ( j ), P   3 ( k ), . . . )= f ( P   1 ( I ), P   2 ( j ), P   3 ( k ), . . . )  (1)  
       
     
     indicating that the computer system performance  105  is a function of the values of various computer system parameters  110 . 
     Computer system performance  105  could then be described by a set of tables as in FIG. 3 for various combinations of two computer system parameters  311 , 312  wherein the remainder of the computer system parameters  110  have constant or nearly constant values for each of the computer system performance values  105  indicated in a given table. In a representative embodiment, analysis and adjustment of selected computer system parameters  110  would be performed as shown in FIG.  2 . 
     While embodiments disclosed in the present patent document refer to automatic adjustment of computer system parameters, it should be recognized that such adjustments could be made by other means, as for example manually. However, some of the advantages disclosed herein would not be optimized were the system to be implemented with other than automatic adjustment. 
     Representative embodiments as described in the present patent document are advantageous in that they take very little time or effort on the part of the system operator to arrive at an optimal or near optimal system configuration. Additionally, as the usage characteristics and load on the system change, this method finds and recommends improvements to the system, without requiring the operator to continuously monitor and redo previous adjustments that were performed by hand. Another benefit is that this mechanism can be used on a subset of the parameters available on a system. Thus, the operator may choose to use this method to look for improvements in obscure or less understood parameters, and make the macroscopic adjustments himself. 
     In addition, this method can be used “offline”. This method can be employed on a development or benchmark instance of the application, instead of on the production version. Improved settings could be found with very consumption of operator time, and without risking adverse affects on a production system. The ideal settings obtained using the development system could then be adapted to the production system. 
     It should also be noted that the permissible adjustments for some computer system parameters  110  maybe made only in discrete values, as for example the addition of active computer memory. 
     While the present invention has been described in detail in relation to representative embodiments thereof, the described embodiments have been presented by way of example and not by way of limitation. It will be understood by those skilled in the art that various changes may be made in the form and details of the described embodiments resulting in equivalent embodiment that remains within the scope of the appended claims.