On Tue, 2007-19-06 at 15:28 -0700, David Miller wrote: > Converting pktgen over to ktime_t might be a nice cleanup.
Would that really solve it? i.e doesnt it still tie to what the clock source is? I had a friend of mine (Robert, you know Jeremy) and results are slightly different from what Evginy found. The summary is: Batching always is better, jiffies is always the better clock source (and who would have thunk,eh? Opteron kicks a Xeons ass). Attached results. Evgeniy, did you sync on the batching case with the git tree? Can you describe your hardware in /proc/cpuinfo and /proc/interupts? cheers, jamal
The test variables are: ---------------------- 1) A Intel Xeon[1] machine vs an AMD opteron[2]. 2) A plain 2622-rc4 kernel vs a 2622-rc4 with batching (from git://git.kernel.org/pub/scm/linux/kernel/git/hadi/batch-lin26.git) 3) Different clock sources acpi-pm, jiffies and tsc Test setup ----------- pktgen was used to send from the system under test (where test variables #2-#3 were adjusted) to a second box. CPU affinity was tied to cpu2 in all case to reduce variables in all test cases... Test validation --------------- Throughput results were confirmed to match on receiver and sender (as reported by pktgen) Results ------- The AMD opteron always had better results. The batching kernels always was better than non-batching. The jiffies clock was always the most consistent and gave best performance Kernel-type | acpi-pm clock | jiffies clock | tsc clock | +h/ware | | | | ------------+---------------+---------------+-----------+ 2622-rc4 | 347Kpps | 1.40 Mpps | 1.36Mpps | plain | | | | Intel Xeon | | | | ------------+---------------+---------------+-----------+ 2622-rc4 | 342Kpps | 853 kpps | 821kpps | plain | | | | AMD opteron | | | | ------------+---------------+---------------+-----------+ 2622-rc4 | 615Kpps | 1.46 Mpps | 1.46Mpps | batch | | | | Intel Xeon | | | | ------------+---------------+---------------+-----------+ 2622-rc4 | 633Kpps | 1.18 Mpps | 1.17Mpps | batch | | | | AMD opteron | | | | ------------+---------------+---------------+-----------+ The two systems under test --------------------------- [1]------------- vendor_id : GenuineIntel cpu family : 15 model : 4 model name : Intel(R) Xeon(TM) CPU 2.80GHz stepping : 1 cpu MHz : 2793.329 cache size : 1024 KB physical id : 3 siblings : 2 core id : 0 cpu cores : 1 ------------- [2]------------- vendor_id : AuthenticAMD cpu family : 15 model : 33 model name : Dual Core AMD Opteron(tm) Processor 275 stepping : 2 cpu MHz : 2194.778 cache size : 1024 KB physical id : 1 siblings : 2 core id : 1 cpu cores : 2 ---------------------------------------------
