mirror of https://github.com/BOINC/boinc.git
51 lines
1.8 KiB
HTML
51 lines
1.8 KiB
HTML
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<h2>Measuring and distinguishing hosts</h2>
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<p>
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The core client measures the following aspects of each host:
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<ul>
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<li> CPU performance: integer ops/sec, double-precision floating-point
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ops/sec, and memory bandwidth are measured separately.
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They are measured by a process executing at the same priority
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as BOINC applications,
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so the results will be affected by other processes.
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These measurements are taken at random intervals.
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<li> Number of CPUs.
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<li> Vendor and model of CPU.
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<li> Disk space: free and total.
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<li> Memory: total RAM, CPU cache, and swap space.
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<li> Timezone.
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<li> Last IP address, and count of consecutive same addresses.
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<li> Number of RPCs and time of last RPC.
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<li> Fractions of time that core client runs on host,
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host is connected, and user is active.
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These are computed as exponentially-weighted averages;
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see the class TIME_STATS.
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<li> Operating system name and version.
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<li> Average up- and downstream network bandwidth.
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These are computed as exponentially-weighted averages;
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see the class NET_STATS.
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</ul>
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These quantities are reported in every scheduling RPC,
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and their latest values are stored in the BOINC database.
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<h3>Distinguishing hosts</h3>
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<p>
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Not all systems have an application-readable globally unique ID,
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so we don't take this approach.
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When a host first contacts the scheduling server it
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is assigned a host ID, which it stores in its "state.xml" file.
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<p>
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The BOINC database maintains the RPC sequence number for each host,
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and the host maintains the sequence number in its state.xml file.
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<p>
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To install the BOINC client on a large number of computers,
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users are instructed to copy only the executable
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and the "account.xml" file.
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If the user copies the state.xml file as well,
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the first RPCs from the other hosts will have
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a repeat sequence number; in this case the scheduling server
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creates a new host record and returns its ID.
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