From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ukaea.org.uk (gateway.ukaea.org.uk [194.128.63.74]) by kvack.org (8.8.7/8.8.7) with ESMTP id FAA10665 for ; Fri, 4 Dec 1998 05:42:59 -0500 Message-Id: <98Dec4.104023gmt.66305@gateway.ukaea.org.uk> Date: Fri, 4 Dec 1998 10:41:15 +0000 From: Neil Conway MIME-Version: 1.0 Subject: Re: SWAP: Linux far behind Solaris or I missed something (fwd) References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Linux MM , Jean-Michel.Vansteene@bull.net, "linux-kernel@vger.rutgers.edu" List-ID: Rik van Riel wrote: > > Hi, > > I think we really should be working on this -- anybody > got a suggestion? > > (although the 2.1.130+my patch seems to work very well > with extremely high swap throughput) Since the poster didn't say otherwise, perhaps this test was performed with buffermem/pagecache.min_percent set to their default values, which IIRC add up to 13% of physical RAM (in fact that's PHYSICAL ram, not 13% of available RAM). So take a 1024MB machine, with (say) roughly 16MB used by the kernel and kernel-data. Then subtract 0.13*1024 (133MB !!) and you're left with a paltry 875MB or so. (This assumes that the poster had modified his kernel to handle the full 1024MB btw). So in fact the cache/buffers probably weren't quite filled to their min. values or swapping and poor performance would have set in even earlier than they did (910MB). It's worth taking note I suppose that Solaris *doesn't* have this problem. It's probably not worth a kernel patch to fix the Linux behaviour though; I just reset the values to more sane ones in rc.local. Now let's see if Linux does any better with say 2% for each of the min values... Neil PS: to Jean-Michel: in case you don't know what I mean (though I assume you do), look at /proc/sys/vm/pagecache and buffermem, and Documentation/sysctl/ PPS: I presume that the initial sluggishness of Solaris was due to it throwing away some cache? > > ---------- Forwarded message ---------- > Date: Wed, 02 Dec 1998 16:49:30 +0100 > From: Jean-Michel VANSTEENE > To: linux-kernel > Subject: SWAP: Linux far behind Solaris or I missed something > > I've made some tests to load a computer (1GB memory). > A litle process starts eating 900 MB then slowly eats > the remainder of the memory 1MB by 1MB and does a > "data shake": 200,000 times a memcpy of 4000 bytes > randomly choosen. > > I want to test the swap capability. > > Solaris was used under XWindow, Linux under text > console... What do I forget to comfigure or tune? > Don't let me with such bad values....... > > ------------------------------------------------ > I removed micro seconds displayed by my function > after call to gettimeofday > > megs Solaris Linux > ------------------------------------------------ > 901: 18 secs 9 secs > 902: 11 secs 9 secs > 903: 10 secs 9 secs > 904: 9 secs 9 secs > 905: 9 secs 9 secs > 906: 9 secs 9 secs > 907: 9 secs 9 secs > 908: 9 secs 9 secs > 909: 9 secs 9 secs > 910: 9 secs 13 secs > 911: 9 secs 17 secs > 912: 9 secs 20 secs > 913: 9 secs 24 secs > 914: 9 secs 33 secs > 915: 10 secs 44 secs > 916: 9 secs 56 secs > 917: 9 secs 65 secs > 918: 9 secs 75 secs > 919: 9 secs 81 secs > 920: 9 secs 87 secs > 921: 9 secs 96 secs > 922: 9 secs 108 secs > 923: 9 secs 122 secs > 924: 9 secs 129 secs > 925: 9 secs 142 secs > 926: 9 secs 155 secs > 927: 9 secs 161 secs > > 928 - 977 always 9 secs under solaris > > 978: 10 secs > 979: 10 secs ------- > 980: 11 secs > 981: 14 secs > 982: 17 secs > 983: 21 secs > 984: 28 secs > 985: 32 secs > 986: 26 secs > 987: 18 secs > 988: 19 secs > 989: 24 secs > 990: 29 secs > 991: 41 secs > 992: 48 secs > 993: 85 secs > 994: 86 secs > 995: 91 secs > 996: 92 secs > 997: 93 secs > 998: 97 secs > 999: 83 secs -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org