From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Wilco Dijkstra via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH] AArch64: Add hp-timing.h
Date: Mon, 28 Jun 2021 19:16:14 +0000 [thread overview]
Message-ID: <VE1PR08MB559969A6AE3269E6DC3397C383039@VE1PR08MB5599.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <70c5dbe8-3e6c-5831-6f79-550e15356074@linaro.org>
Hi Adhemerval,
> It is used for LD_DEBUG=statistics to give better profiling numbers
> (theoretically). However, the profiling is still measured in some
> parts even LD_DEBUG is not set unfortunately. It assumes that reading
> the clock is as fast as one instructions, that why it is only enabled
> for HP_TIMING_INLINE.
If emulated, it's over 600 cycles per use, not something you want to
accidentally do by default...
> Not sure if it is worth to enable on aarch64 indeed.
It would be alright if the timing was done conditionally so that there is no
performance hit and there can be no concern that ld.so might crash on an
ancient kernel.
Cheers,
Wilco
next prev parent reply other threads:[~2021-06-28 19:16 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-28 10:11 Wilco Dijkstra
2021-06-28 10:20 ` Florian Weimer
2021-06-28 10:53 ` Wilco Dijkstra
2021-06-28 11:06 ` Florian Weimer
2021-06-28 11:35 ` Wilco Dijkstra
2021-06-28 11:39 ` Florian Weimer
2021-06-28 11:49 ` Szabolcs Nagy
2021-06-28 11:55 ` Adhemerval Zanella
2021-06-28 12:10 ` Wilco Dijkstra
2021-06-28 13:15 ` Adhemerval Zanella
2021-06-28 14:24 ` Wilco Dijkstra
2021-06-28 14:46 ` Adhemerval Zanella
2021-06-28 19:16 ` Wilco Dijkstra [this message]
2021-06-30 8:46 ` Szabolcs Nagy
2021-06-30 8:55 ` Florian Weimer
2021-06-30 9:33 ` Siddhesh Poyarekar
2021-07-01 10:21 ` Wilco Dijkstra
2021-07-01 13:48 ` Szabolcs Nagy
2021-07-01 15:33 ` Wilco Dijkstra
2021-07-06 11:33 ` Florian Weimer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=VE1PR08MB559969A6AE3269E6DC3397C383039@VE1PR08MB5599.eurprd08.prod.outlook.com \
--to=wilco.dijkstra@arm.com \
--cc=adhemerval.zanella@linaro.org \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).