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Re: [PATCH] Simple malloc benchtest.
- From: Siddhesh Poyarekar <siddhesh dot poyarekar at gmail dot com>
- To: Ondřej Bílka <neleai at seznam dot cz>
- Cc: GNU C Library <libc-alpha at sourceware dot org>, Siddhesh Poyarekar <siddhesh at redhat dot com>
- Date: Mon, 23 Dec 2013 23:29:02 +0530
- Subject: Re: [PATCH] Simple malloc benchtest.
- Authentication-results: sourceware.org; auth=none
- References: <20131221153303 dot GA8420 at domone dot podge> <20131223090627 dot GF4979 at spoyarek dot pnq dot redhat dot com> <20131223095034 dot GA20816 at domone> <20131223110912 dot GG4979 at spoyarek dot pnq dot redhat dot com> <20131223133157 dot GB20816 at domone> <CAAHN_R2+N432brpObQ9RK4cJgjcqvpf+gtF7J4b1wwMShFQu7A at mail dot gmail dot com> <CAAHN_R3k-rydhVTKzV9ovC8+ykhvP+8Stx+rfZ=XbTfwBs29Lg at mail dot gmail dot com> <20131223163025 dot GA4911 at domone>
On 23 December 2013 22:00, OndÅej BÃlka <neleai@seznam.cz> wrote:
> No that would be bad first step. Tweak could look like improvement in
> simple tests but really be a regression in real world. And if you have
> real world data then simulated data are useless.
You're again talking about microbenchmarks vs system benchmarks, which
is honestly just a waste of time and in this thread, it is
contradicting your own point of introducing an initial simple
microbenchmark.
> When you want to compare alternative allocator you need to check effects of
> fragmentation, number of cache misses, RSS and virtual memory size and other
> factors on hooked applications and there is no shortcut around that.
You need all this to form a complete picture of the performance of an
allocator regardless of whether you're comparing with another
allocator or not. That is, ideally one ought to be looking at the
impact of a change in an allocator on all these parameters, but you
need to start somewhere. I thought the intention of your patch was to
make that start, so if you're saying that it's not useful then you're
essentially contradicting yourself.
Siddhesh
--
http://siddhesh.in