Great News!! Was: [RFT] 2.2.8_andrea1 wake-one

Phillip Ezolt (ezolt@perf.zko.dec.com)
Fri, 14 May 1999 16:09:21 -0400 (EDT)


Hi all, (especially Andrea)
I've been doing some more SPECWeb96 tests, and with Andrea's
patch to 2.2.8 (ftp://e-mind.com/pub/andrea/kernel/2.2.8_andrea1.bz)

**On identical hardware, I get web-performance nearly identical to Tru64!**

Previously, Linux response times had been 100ms while tru64 had been ~4ms.

However, with this patch applied, linux reponse times almost mirror Tru64.

Tru64 ~4ms
2.2.5 ~100ms
2.2.8 ~9ms
2.2.8_a ~4ms

I realize that 2.3.1 has a more efficient wakeone patch applied, and haven't
yet had a chance to try it. (Maybe tonight)

Time spent in schedule has decreased, as shown by this Iprobe data:

2.2.8 (pure)

Begin End Sample Image Total
Address Address Name Count Pct Pct
------- ------- ---- ----- --- ---
0000000000000000-0000000120006F2F /usr/bin/httpd 121077 19.2
0000000120041A00-00000001200433FF ap_vformatter 14777 12.2 2.3
FFFFFC0000300000-00000000FFFFFFFF vmlinux 428086 67.9
FFFFFC0000315FA0-FFFFFC00003160DF do_entInt 40185 9.4 6.4
FFFFFC0000327D20-FFFFFC000032805F schedule 126434 29.5 20.0
FFFFFC00003B9CC0-FFFFFC00003BA0BF tcp_v4_rcv 11701 2.7 1.9
FFFFFC00003DB3A0-FFFFFC00003DBA5F make_request 6879 1.6 1.1
FFFFFC00004446E0-FFFFFC0000444ABF do_csum_partial 27835 6.5 4.4
_copy_from_user
FFFFFC0000445340-FFFFFC0000445513 __copy_user 9722 2.3 1.5

2.2.8 (w/2.2.8_andrea1.bz)

Begin End Sample Image Total
Address Address Name Count Pct Pct
------- ------- ---- ----- --- ---
0000000000000000-0000000120006F2F /usr/bin/httpd 121882 22.5
0000000120041A00-00000001200433FF ap_vformatter 15166 12.4 2.8
0000020000590000-0000020000772FFF /lib/libc-2.0.7.so 66412 12.2
00000200005F4E20-00000200005F4F7F memcpy 6168 9.3 1.1
FFFFFC0000300000-00000000FFFFFFFF vmlinux 343294 63.2
FFFFFC0000316020-FFFFFC000031615F do_entInt 42469 12.4 7.8
FFFFFC0000327DA0-FFFFFC000032811F schedule 37676 11.0 6.9
FFFFFC0000328120-FFFFFC00003281FF __wake_up 21703 6.3 4.0
FFFFFC00003AF940-FFFFFC00003AFA7F wait_for_connect 5489 1.6 1.0
FFFFFC00003BA3C0-FFFFFC00003BA7BF tcp_v4_rcv 7012 2.0 1.3
FFFFFC0000444F80-FFFFFC000044535F do_csum_partial 27679 8.1 5.1
_copy_from_user
FFFFFC0000445BE0-FFFFFC0000445DB3 __copy_user 9188 2.7 1.7

The number of SPECWeb96 MaxOps per second have jumped has well.

**Please, put the wakeone patch into the 2.2.X kernel if it isn't already. **

--Phil

Compaq HPSD/Benchmark Performance Engineering
Phillip.Ezolt@compaq.com ezolt@perf.zko.dec.com

On Wed, 12 May 1999, Andrea Arcangeli wrote:

> On Fri, 7 May 1999, Andrea Arcangeli wrote:
>
> >I'll provide you a patch shortly to try out.
>
> Phillip, could you try it out:
>
> ftp://e-mind.com/pub/andrea/kernel/2.2.8_andrea1.bz2
>
> under heavy web load? (should run fine on alpha too as far as stock-2.2.8
> is just fine too)
>
> Note: it has also my wake-one on accept that just address completly the
> overscheduling problem. But to achieve performances by it you must make
> sure that _all_ apache tasks are sleeping in accept(2) and not in
> flock(2)/fcntl(2)/whatever. Maybe you'll need to patch apache to achieve
> that (I also seen a patch floating on the list, maybe you only need to
> grap such patch and apply/reverse it over the apache tree).
>
> I would like if you would make comparison with a clean 2.2.8 (or with
> pre-2.3.1 even if I have not seen it yet).
>
> Andrea Arcangeli
>
>
>

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