From: DJ Delorie <dj@redhat.com>
To: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: carlos@redhat.com, libc-alpha@sourceware.org, nd@arm.com
Subject: Re: [PATCH] Add malloc micro benchmark
Date: Thu, 28 Dec 2017 14:01:15 -0500 [thread overview]
Message-ID: <xnwp167k3o.fsf@greed.delorie.com> (raw)
In-Reply-To: <DB6PR0801MB2053D2E9BF766A9EF7F47E3B83040@DB6PR0801MB2053.eurprd08.prod.outlook.com> (message from Wilco Dijkstra on Thu, 28 Dec 2017 14:09:29 +0000)
Wilco Dijkstra <Wilco.Dijkstra@arm.com> writes:
> Yes I'd be interested in the traces. I presume they are ISA independent and
> can just be replayed?
Yup, they're ISA-agnostic compressed pseudo-codes that run a state
machine. I put them here (except the two biggest, which take days to
transfer):
http://www.delorie.com/malloc/
Be kind, that's my house's bandwidth ;-)
The simulator is in the dj/malloc branch, in malloc/trace_run.c
> I think in many of these cases we can be far smarter and use adaptive
> algorithms.
I'm wary of "smart" algorithms because it's so hard to generalize them
to work sufficiently well in all cases, without accidentally causing
super-stupid behavior in some unusual app.
But yeah :-)
> Longer term we need to make arena's per-thread - see below.
They're sort of per-thread now, but a lot of apps pass malloc'd memory
between threads. A strict one-per-thread isn't optimal either.
> My observation was that the gains from tcache are due to bypassing
> completely uncontended locks.
Yup.
> If an arena could be marked as owned by
> a thread,
That mark would need to be an uncontended lock...
>> 2. When we say a patch "is faster", let's run all our benchmarks and
>> make sure that we don't mean "on some benchmarks." The whole point
>> of the trace/sim stuff is to make sure key downstream users aren't
>> left out of the optimization work, and end up with worse performance.
>
> Well you can't expect gains on all benchmarks or have a "never regress
> anything ever" rule.
Sure, I just don't want surprises. Also, benchmarks from the Real World
can be prioritized - a patch which improves a synthetic benchmark but
makes chrome worse should be rejected. A generally good patch that
makes a few apps worse should at least be investigated to find out why.
Etc.
> Szabolcs or I would be happy to run the traces on AArch64.
That would be helpful :-)
next prev parent reply other threads:[~2017-12-28 18:59 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-01 13:51 [PATCH] Add malloc micro benchmark Wilco Dijkstra
2017-12-01 16:13 ` Carlos O'Donell
2017-12-18 15:18 ` Wilco Dijkstra
2017-12-18 16:32 ` Carlos O'Donell
2018-01-02 18:20 ` [PATCH v2] " Wilco Dijkstra
2018-01-02 18:45 ` DJ Delorie
2018-01-03 12:12 ` Wilco Dijkstra
2018-01-03 15:07 ` Carlos O'Donell
2018-01-04 13:48 ` Wilco Dijkstra
2018-01-04 16:37 ` Adhemerval Zanella
2018-01-05 14:32 ` Carlos O'Donell
2018-01-05 15:50 ` Adhemerval Zanella
2018-01-05 16:17 ` Carlos O'Donell
2018-01-05 16:46 ` Adhemerval Zanella
2018-01-05 17:27 ` Carlos O'Donell
2018-01-05 14:33 ` Carlos O'Donell
2018-01-05 16:28 ` Joseph Myers
2018-01-05 17:26 ` Carlos O'Donell
2018-02-28 12:40 ` Florian Weimer
2018-02-28 14:11 ` Ondřej Bílka
2018-02-28 14:16 ` Florian Weimer
2018-02-28 16:16 ` Carlos O'Donell
2018-02-28 20:17 ` Ondřej Bílka
2018-02-28 16:46 ` Ondřej Bílka
2018-02-28 17:01 ` Wilco Dijkstra
2018-02-28 18:21 ` Carlos O'Donell
2018-02-28 19:56 ` Ondřej Bílka
2018-02-28 21:56 ` DJ Delorie
2018-03-01 11:24 ` Ondřej Bílka
2017-12-18 23:02 ` [PATCH] " DJ Delorie
2017-12-28 14:09 ` Wilco Dijkstra
2017-12-28 19:01 ` DJ Delorie [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-02-01 16:27 Wilco Dijkstra
2019-02-08 19:37 ` DJ Delorie
2019-02-14 16:38 ` Wilco Dijkstra
2019-02-14 20:42 ` DJ Delorie
2019-02-28 4:52 ` Carlos O'Donell
2019-03-04 17:35 ` Wilco Dijkstra
2019-03-18 17:16 ` Wilco Dijkstra
2019-04-09 5:25 ` Carlos O'Donell
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