From: Milton Miller <miltonm@bga.com>
To: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@ozlabs.org
Subject: [PATCH 5/6] depend on ->initialized in calc_steal_time
Date: Thu, 13 Dec 2007 22:52:19 -0600 (CST) [thread overview]
Message-ID: <mm-cpu-5@bga.com> (raw)
In-Reply-To: <mm-cpu-0@bga.com>
If CPU_FTR_PURR is not set, we will never set cpu_purr_data->initialized.
Checking via __get_cpu_var on 64 bit avoids one dependent load compared
to cpu_has_feature in the not present case, and is always required when
it is present. The code is under CONFIG_VIRT_CPU_ACCOUNTING so 32 bit
will not be affected.
Signed-off-by: Milton Miller <miltonm@bga.com>
---
Index: kernel/arch/powerpc/kernel/time.c
===================================================================
--- kernel.orig/arch/powerpc/kernel/time.c 2007-12-13 18:16:10.000000000 -0600
+++ kernel/arch/powerpc/kernel/time.c 2007-12-13 18:23:55.000000000 -0600
@@ -329,11 +329,9 @@ void calculate_steal_time(void)
s64 stolen;
struct cpu_purr_data *pme;
- if (!cpu_has_feature(CPU_FTR_PURR))
- return;
pme = &__get_cpu_var(cpu_purr_data);
if (!pme->initialized)
- return; /* this can happen in early boot */
+ return; /* !CPU_FTR_PURR or early in early boot */
tb = mftb();
purr = mfspr(SPRN_PURR);
stolen = (tb - pme->tb) - (purr - pme->purr);
next prev parent reply other threads:[~2007-12-14 4:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-14 4:51 [PATCH 0/6] xics.c and time.c optimizations Milton Miller
2007-12-14 4:52 ` [PATCH 1/6] push down or eliminate smp_processor_id in xics Milton Miller
2007-12-14 4:52 ` [PATCH 3/6] use __get_cpu_var in time.c Milton Miller
2007-12-14 4:52 ` [PATCH 2/6] init_decrementer_clockevent can be static __init Milton Miller
2007-12-14 4:52 ` [PATCH 4/6] timer interrupt: use a struct for two per_cpu varables Milton Miller
2007-12-14 4:52 ` Milton Miller [this message]
2007-12-14 4:52 ` [PATCH 6/6] optimize account_system_vtime Milton Miller
2007-12-15 2:10 ` Michael Neuling
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=mm-cpu-5@bga.com \
--to=miltonm@bga.com \
--cc=linuxppc-dev@ozlabs.org \
--cc=paulus@samba.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 NNTP newsgroup(s).