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Message-ID: <51d9cfa4-e322-9fb6-bc1f-b2c6ccc68bf8@suse.cz>
Date: Fri, 2 Jun 2017 10:30:46 +0200
From: Jiri Slaby <jslaby@...e.cz>
To: Ingo Molnar <mingo@...nel.org>,
Josh Poimboeuf <jpoimboe@...hat.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
live-patching@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Andy Lutomirski <luto@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Peter Zijlstra <peterz@...radead.org>
Subject: Re: [RFC PATCH 00/10] x86: undwarf unwinder
On 06/01/2017, 03:58 PM, Jiri Slaby wrote:
> On 06/01/2017, 03:50 PM, Ingo Molnar wrote:
>> That's not what I meant! The speedup comes from (hopefully) being able to disable
>> CONFIG_FRAME_POINTER, which:
>
> BTW when you are mentioning this -- my measurements were with FP disabled.
>
> Is there any reasonably simple-to-use benchmark I could run with FP=y
> and FP=n quickly?
Nevermind, I tried 10000000 stack unwindings several times and ran
netperf too. Both on the same virtual machine. On these microbenchmarks,
the former performs ~ 1.03 times better, the latter ~ 1.3 times. When
Mel measured the difference, it was around 10 % overall using more
sophisticated benchmarks.
With FP=n:
# time echo 10000000 > /dev/test_dwarf
real 0m6.659s
user 0m0.000s
sys 0m6.655s
# for aa in 1 0 0 0 0; do netperf -P $aa ; done
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
localhost () port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 10.00 47819.30
87380 16384 16384 10.00 41991.01
87380 16384 16384 10.00 43607.82
87380 16384 16384 10.00 42208.44
87380 16384 16384 10.00 44383.92
With FP=y:
# time echo 10000000 > /dev/test_dwarf
real 0m6.869s
user 0m0.000s
sys 0m6.868s
# for aa in 1 0 0 0 0; do netperf -P $aa ; done
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
localhost () port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 10.00 37807.90
87380 16384 16384 10.00 32246.67
87380 16384 16384 10.00 31358.76
87380 16384 16384 10.00 32450.00
87380 16384 16384 10.00 31326.70
thanks,
--
js
suse labs
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