On Wed, 28 Jan 2004 12:43:10 -0500, John Baldwin <jhb_at_FreeBSD.org> wrote: > On Tuesday 27 January 2004 05:19 pm, Peter Losher wrote: >> On Tuesday 27 January 2004 10:34 am, John Baldwin wrote: >> > This is a very hard to debug problem. If WITNESS is on it provides >> more >> > useful information that can help track that down, but I wouldn't >> expect a >> > production machine to be using WITNESS. >> >> Yes, I was running a kernel for a short while w/ INVARIANTS and WITNESS, >> but it was basically useless after a couple of hours under load under >> the >> giant lock. How much of a performance hit is just WITNESS? > > A lot. I think Robert Watson has seen as high a performance impact as > 40%. I have played with the bytebench few days ago, just for fun... This machine that I played is 464Mhz and 386mb ram; it uses libkse and ULE (four days ago -CURRENT). W/OUT-DEBUG = Remove all debug options from kernel and set /etc/malloc.conf->aj.. ================================= --W/-DEBUG-- -W/OUT-DEBUG- Dhrystone 2 without register variables 1105081.4 lps 1097325.0 lps Dhrystone 2 using register variables 1100857.8 lps 1109398.3 lps Arithmetic Test (type = arithoh) 2076290.3 lps 2086816.9 lps Arithmetic Test (type = register) 125288.4 lps 126051.2 lps Arithmetic Test (type = short) 125818.8 lps 126406.5 lps Arithmetic Test (type = int) 125481.3 lps 126101.5 lps Arithmetic Test (type = long) 125293.6 lps 126067.5 lps Arithmetic Test (type = float) 145203.2 lps 146956.6 lps Arithmetic Test (type = double) 145017.1 lps 145718.5 lps System Call Overhead Test 11830.6 lps 109590.1 lps Pipe Throughput Test 20572.7 lps 96916.4 lps Pipe-based Context Switching Test 6856.2 lps 25128.9 lps Process Creation Test 155.1 lps 865.2 lps Execl Throughput Test 62.7 lps 261.0 lps File Read (10 seconds) 40538.0 KBps 246172.0 KBps File Write (10 seconds) 7033.0 KBps 11565.0 KBps File Copy (10 seconds) 4907.0 KBps 12555.0 KBps File Read (30 seconds) 40688.0 KBps 246785.0 KBps File Write (30 seconds) 7022.0 KBps 11343.0 KBps File Copy (30 seconds) 4763.0 KBps 12400.0 KBps C Compiler Test 187.1 lpm 327.1 lpm Shell scripts (1 concurrent) 98.0 lpm 623.6 lpm Shell scripts (2 concurrent) 50.6 lpm 326.3 lpm Shell scripts (4 concurrent) 26.0 lpm 168.0 lpm Shell scripts (8 concurrent) 13.0 lpm 82.0 lpm Dc: sqrt(2) to 99 decimal places 5299.0 lpm 31721.7 lpm Recursion Test--Tower of Hanoi 11543.3 lps 11618.8 lps INDEX VALUES ---------W/-DEBUG--------- --------W/OUT-DEBUG------- TEST BASELINE RESULT INDEX BASELINE RESULT INDEX Arithmetic Test (type = double) 2541.7 145017.1 57.1 2541.7 145718.5 57.3 Dhrystone 2 without register variables 22366.3 1105081.4 49.4 22366.3 1097325.0 49.1 Execl Throughput Test 16.5 62.7 3.8 16.5 261.0 15.8 File Copy (30 seconds) 179.0 4763.0 26.6 179.0 12400.0 69.3 Pipe-based Context Switching Test 1318.5 6856.2 5.2 1318.5 25128.9 19.1 Shell scripts (8 concurrent) 4.0 13.0 3.2 4.0 82.0 20.5 ========= ========= SUM of 6 items 145.3 231.0 AVERAGE 24.2 38.5 ================================= Cheers, Mezz -- bsdforums.org 's moderator, mezz.Received on Wed Jan 28 2004 - 09:51:40 UTC
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