From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Juergen Gross <jgross@suse.com>,
keir@xen.org, jbeulich@suse.com, dario.faggioli@citrix.com,
george.dunlap@eu.citrix.com, xen-devel@lists.xen.org
Subject: Re: [PATCH 0/5] use mask operations instead of test_bit()
Date: Fri, 2 Oct 2015 10:47:39 +0100 [thread overview]
Message-ID: <560E52BB.1080004@citrix.com> (raw)
In-Reply-To: <1443760830-29095-1-git-send-email-jgross@suse.com>
On 02/10/15 05:40, Juergen Gross wrote:
> Instead of using test_bit() which is an atomic operation and limits
> the compiler's choices to do optimization, use logical ANDs with
> bitmasks where possible.
>
> The possible candidates have been detected by searching definitions
> of bitmasks in the form:
>
> #define MASK 1 << _MASK
>
> On x86 the resulting code is slightly smaller (about 2 bytes for each
> case, checked via disassembly in few examples).
>
> I'm quite sure I didn't replace a test_bit() call required to be
> atomic, but I'd be grateful for a thorough review especially in the
> scheduler.
>
>
> Juergen Gross (5):
> xen: use masking operation instead of test_bit for RTDS bits
> xen: use masking operation instead of test_bit for CSFLAG bits
> xen: use masking operation instead of test_bit for VGCF bits
> xen: use masking operation instead of test_bit for VPF bits
> xen: use masking operation instead of test_bit for MCSF bits
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
prev parent reply other threads:[~2015-10-02 9:47 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 4:40 [PATCH 0/5] use mask operations instead of test_bit() Juergen Gross
2015-10-02 4:40 ` [PATCH 1/5] xen: use masking operation instead of test_bit for RTDS bits Juergen Gross
2015-10-02 10:21 ` Dario Faggioli
2015-10-05 13:30 ` George Dunlap
2015-10-02 4:40 ` [PATCH 2/5] xen: use masking operation instead of test_bit for CSFLAG bits Juergen Gross
2015-10-02 10:45 ` Dario Faggioli
2015-10-05 13:30 ` George Dunlap
2015-10-02 4:40 ` [PATCH 3/5] xen: use masking operation instead of test_bit for VGCF bits Juergen Gross
2015-10-02 4:40 ` [PATCH 4/5] xen: use masking operation instead of test_bit for VPF bits Juergen Gross
2015-10-05 13:18 ` George Dunlap
2015-10-05 13:36 ` Jan Beulich
2015-10-05 13:45 ` George Dunlap
2015-10-05 14:05 ` Jan Beulich
2015-10-05 14:31 ` George Dunlap
2015-10-05 13:39 ` Juergen Gross
2015-10-05 13:24 ` George Dunlap
2015-10-05 13:40 ` Jan Beulich
2015-10-02 4:40 ` [PATCH 5/5] xen: use masking operation instead of test_bit for MCSF bits Juergen Gross
2015-10-02 9:03 ` [PATCH 0/5] use mask operations instead of test_bit() Dario Faggioli
2015-10-02 9:10 ` Juergen Gross
2015-10-02 9:33 ` Dario Faggioli
2015-10-02 9:44 ` Jan Beulich
2015-10-02 9:47 ` Andrew Cooper [this message]
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