Messages in this thread | | | Date | Thu, 3 Aug 2000 17:35:18 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: [benchmark] 2.4.0-test6-pre1 PAE vs non-PAE |
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the 3% performance drop is mainly due to two values, 'Pipe-based Context Switching', 'Process Creation', and 'Execl Throughput'. The fork() and exec() result is understandably worse with PAE, because the 'density' of page-tables is half of that of non-PAE page-tables (ie. twice as much has to be copied), plus there are 3 user-space root page tables instead of the 1. (which have to be zeroed, so this shows up big time.)
Another performance problem is likely the amount of LOCK-ed instructions done within the PAE include-files - some of that is unnecessery as David S. Miller noticed.
otherwise the PAE kernels show no performance drop in 'typical' user-space stuff. But yes, you dont want to use it on a box with less than 4GB RAM.
Ingo
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